bug#4818: 23.1; checkdoc noun at end of sentence

[Chong Yidong]

> Running M-x checkdoc over the foo.el below I hoped it would ask to
> capitalize "emacs" to "Emacs" in each of the three places.  A real-life
> example can be found in `vi-save-all-and-exit' of vi.el.

> I suspect the \\_> in checkdoc-proper-noun-regexp doesn't match a "." at
> the end of a sentence.  Would relaxing that a bit like below cause any
> false positives?

Look OK, feel free to check in (and close this bug).