Switch clang-tidy config comment format (#5458)

With the clang-19 minimum, we can intermingle comments.

.clang-tidy

@@ -8,118 +8,94 @@ UseColor: true
 # This is necessary for `--config=clang-tidy` to catch errors.
 WarningsAsErrors: '*'
 
-# TODO: clang-tidy-16 doesn't support this format; it's retained for comments.
-# Switch once we update the minimum version.
-#
-# # We turn on all of a few categories by default.
-# - '-*'
-# - 'bugprone-*'
-# - 'google-*'
-# - 'misc-*'
-# - 'modernize-*'
-# - 'performance-*'
-# - 'readability-*'
-#
-# # Disabled due to the implied style choices.
-# - '-misc-const-correctness'
-# - '-misc-include-cleaner'
-# - '-misc-use-anonymous-namespace'
-# - '-modernize-return-braced-init-list'
-# - '-modernize-use-default-member-init'
-# - '-modernize-use-integer-sign-comparison'
-# - '-modernize-use-emplace'
-# - '-readability-avoid-nested-conditional-operator'
-# - '-readability-convert-member-functions-to-static'
-# - '-readability-else-after-return'
-# - '-readability-identifier-length'
-# - '-readability-implicit-bool-conversion'
-# - '-readability-make-member-function-const'
-# - '-readability-math-missing-parentheses'
-# - '-readability-static-definition-in-anonymous-namespace'
-# - '-readability-use-anyofallof'
-#
-# # Warns when we have multiple empty cases in switches, which we do for comment
-# # reasons.
-# - '-bugprone-branch-clone'
-# # Frequently warns on multiple parameters of the same type.
-# - '-bugprone-easily-swappable-parameters'
-# # Finds issues like out-of-memory in main(). We don't use exceptions, so it's
-# # unlikely to find real issues.
-# - '-bugprone-exception-escape'
-# # Has false positives in places such as using an argument to declare a name,
-# # which cannot have parentheses. For our limited use of macros, this is a
-# # common conflict.
-# - '-bugprone-macro-parentheses'
-# # Conflicts with integer type C++ style.
-# - '-bugprone-narrowing-conversions'
-# # Has false positives for `enum_base.h`. Clang's built-in switch warnings
-# # cover most of our risk of bugs here.
-# - '-bugprone-switch-missing-default-case'
-# # In clang-tidy 16, has false positives on code like:
-# #     while (auto name_ref = insts().Get(inst_id).TryAs<SemIR::NameRef>()) {
-# #       inst_id = name_ref->value_id;
-# #                 ^ unchecked access to optional value
-# #     }
-# - '-bugprone-unchecked-optional-access'
-# # Overlaps with `readability-function-size`.
-# - '-google-readability-function-size'
-# # Suggests usernames on TODOs, which we don't want.
-# - '-google-readability-todo'
-# # Extremely slow. TODO: Re-enable once
-# # https://github.com/llvm/llvm-project/issues/128797 is fixed.
-# - '-misc-confusable-identifiers'
-# # Overlaps with `-Wno-missing-prototypes`.
-# - '-misc-use-internal-linkage'
-# # Suggests `std::array`, which we could migrate to, but conflicts with the
-# # status quo.
-# - '-modernize-avoid-c-arrays'
-# # Warns on creation of SemIR typed insts, for which we do not currently want
-# # to use designated initialization.
-# - '-modernize-use-designated-initializers'
-# # Only fixes const methods, not non-const, which yields distracting results on
-# # accessors.
-# - '-modernize-use-nodiscard'
-# # We aren't using the ranges library due to performance concerns.
-# - '-modernize-use-ranges'
-# # Low value compared to the engineering cost.
-# - '-performance-enum-size'
-# # Duplicates `modernize-pass-by-value`.
-# - '-performance-unnecessary-value-param'
-# # Warns on enums which use the `LastValue = Value` pattern if all the other
-# # discriminants aren't given an explicit value.
-# - '-readability-enum-initial-value'
-# # Warns too frequently.
-# - '-readability-function-cognitive-complexity'
-# # Warns in reasonably documented situations.
-# - '-readability-magic-numbers'
-# # Warns on `= {}` which is also used to indicate which fields do not need to
-# # be explicitly initialized in aggregate initialization.
-# - '-readability-redundant-member-init'
-# # Warns when callers use similar names as different parameters.
-# - '-readability-suspicious-call-argument'
 Checks:
-  -*, bugprone-*, google-*, misc-*, modernize-*, performance-*, readability-*,
-  -misc-const-correctness, -misc-include-cleaner, -misc-use-anonymous-namespace,
-  -modernize-return-braced-init-list, -modernize-use-default-member-init,
-  -modernize-use-integer-sign-comparison, -modernize-use-emplace,
-  -readability-avoid-nested-conditional-operator,
-  -readability-convert-member-functions-to-static,
-  -readability-else-after-return, -readability-identifier-length,
-  -readability-implicit-bool-conversion,
-  -readability-make-member-function-const,
-  -readability-math-missing-parentheses,
-  -readability-static-definition-in-anonymous-namespace,
-  -readability-use-anyofallof, -bugprone-branch-clone,
-  -bugprone-easily-swappable-parameters, -bugprone-exception-escape,
-  -bugprone-macro-parentheses, -bugprone-narrowing-conversions,
-  -bugprone-switch-missing-default-case, -bugprone-unchecked-optional-access,
-  -google-readability-function-size, -google-readability-todo,
-  -misc-confusable-identifiers, -misc-use-internal-linkage,
-  -modernize-avoid-c-arrays, -modernize-use-designated-initializers,
-  -modernize-use-nodiscard, -modernize-use-ranges, -performance-enum-size,
-  -performance-unnecessary-value-param, -readability-enum-initial-value,
-  -readability-function-cognitive-complexity, -readability-magic-numbers,
-  -readability-redundant-member-init, -readability-suspicious-call-argument
+  # We turn on all of a few categories by default.
+  - '-*'
+  - 'bugprone-*'
+  - 'google-*'
+  - 'misc-*'
+  - 'modernize-*'
+  - 'performance-*'
+  - 'readability-*'
+
+  # Disabled due to the implied style choices.
+  - '-misc-const-correctness'
+  - '-misc-include-cleaner'
+  - '-misc-use-anonymous-namespace'
+  - '-modernize-return-braced-init-list'
+  - '-modernize-use-default-member-init'
+  - '-modernize-use-integer-sign-comparison'
+  - '-modernize-use-emplace'
+  - '-readability-avoid-nested-conditional-operator'
+  - '-readability-convert-member-functions-to-static'
+  - '-readability-else-after-return'
+  - '-readability-identifier-length'
+  - '-readability-implicit-bool-conversion'
+  - '-readability-make-member-function-const'
+  - '-readability-math-missing-parentheses'
+  - '-readability-static-definition-in-anonymous-namespace'
+  - '-readability-use-anyofallof'
+
+  # Warns when we have multiple empty cases in switches, which we do for comment
+  # reasons.
+  - '-bugprone-branch-clone'
+  # Frequently warns on multiple parameters of the same type.
+  - '-bugprone-easily-swappable-parameters'
+  # Finds issues like out-of-memory in main(). We don't use exceptions, so it's
+  # unlikely to find real issues.
+  - '-bugprone-exception-escape'
+  # Has false positives in places such as using an argument to declare a name,
+  # which cannot have parentheses. For our limited use of macros, this is a
+  # common conflict.
+  - '-bugprone-macro-parentheses'
+  # Conflicts with integer type C++ style.
+  - '-bugprone-narrowing-conversions'
+  # Has false positives for `enum_base.h`. Clang's built-in switch warnings
+  # cover most of our risk of bugs here.
+  - '-bugprone-switch-missing-default-case'
+  # In clang-tidy 16, has false positives on code like:
+  #     while (auto name_ref = insts().Get(inst_id).TryAs<SemIR::NameRef>()) {
+  #       inst_id = name_ref->value_id;
+  #                 ^ unchecked access to optional value
+  #     }
+  - '-bugprone-unchecked-optional-access'
+  # Overlaps with `readability-function-size`.
+  - '-google-readability-function-size'
+  # Suggests usernames on TODOs, which we don't want.
+  - '-google-readability-todo'
+  # Extremely slow. TODO: Re-enable once
+  # https://github.com/llvm/llvm-project/issues/128797 is fixed.
+  - '-misc-confusable-identifiers'
+  # Overlaps with `-Wno-missing-prototypes`.
+  - '-misc-use-internal-linkage'
+  # Suggests `std::array`, which we could migrate to, but conflicts with the
+  # status quo.
+  - '-modernize-avoid-c-arrays'
+  # Warns on creation of SemIR typed insts, for which we do not currently want
+  # to use designated initialization.
+  - '-modernize-use-designated-initializers'
+  # Only fixes const methods, not non-const, which yields distracting results on
+  # accessors.
+  - '-modernize-use-nodiscard'
+  # We aren't using the ranges library due to performance concerns.
+  - '-modernize-use-ranges'
+  # Low value compared to the engineering cost.
+  - '-performance-enum-size'
+  # Duplicates `modernize-pass-by-value`.
+  - '-performance-unnecessary-value-param'
+  # Warns on enums which use the `LastValue = Value` pattern if all the other
+  # discriminants aren't given an explicit value.
+  - '-readability-enum-initial-value'
+  # Warns too frequently.
+  - '-readability-function-cognitive-complexity'
+  # Warns in reasonably documented situations.
+  - '-readability-magic-numbers'
+  # Warns on `= {}` which is also used to indicate which fields do not need to
+  # be explicitly initialized in aggregate initialization.
+  - '-readability-redundant-member-init'
+  # Warns when callers use similar names as different parameters.
+  - '-readability-suspicious-call-argument'
+
 CheckOptions:
   # Don't warn on structs; done by ignoring when there are only public members.
   - key: misc-non-private-member-variables-in-classes.IgnoreClassesWithAllMemberVariablesBeingPublic