Finish an incomplete sentence in p2551. (#2554)

This was discussed in person with at least two of the leads while
drafting the text, but sadly it did not finish being typed into the
document.

Just amending the proposal text for the future as I don't think it
substantively changes the conclusions.

Thanks to @geoffromer for noticing this!

proposals/p2551.md

@@ -91,8 +91,9 @@ as being an _active_ participant. Some other measures:
     below 50% from any single organization.
 -   We had 258 issue commenters, and 64 making over 4 comments over the course
     of the year, both _far_ below 50% from a single organization.
--   Looking at the weekly meetings in August, September, and October, we had a
-    bit
+-   Looking at the weekly meetings in August, September, and October, we had
+    just under 50% of the meetings with less than 50% of attendees from a single
+    organization.
 
 Largely, we feel we hit this goal solidly. However, we still see specific areas
 where we need to broaden participation, for example: