bug#24663: 24.5; doc string of `completion-at-point-functions'

[Drew Adams]

1. Some lines are too long.  Please use fill-column=70 for ordinary
paragraphs.

2. Typo: "in turns" should be ", in turn," (no "s").

3. "the thing at point" means nothing.  Thing at point means something
only for a given type of THING.  There is not just one ("the") thing
at point.

Presumably what is meant here is not a thing at point but some text
preceding point.  It is some text before point that is completed.

4. Add a comma after "nil".

5. Typo: "function of no argument" should be "function of no arguments".

6. " where" should be ", where:" (and that sentence is run-on (too
long).

7. "responsible to preserve" should be "responsible for preserving".


In GNU Emacs 24.5.1 (i686-pc-mingw32)
 of 2015-04-11 on LEG570
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --prefix=/c/usr --host=i686-pc-mingw32'