bug#54047: 26.3; Doc of `fill-region-as-paragraph'

[Drew Adams]

1. The doc string isn't clear at all wrt arguments NOSQUEEZE and
SQUEEZE-AFTER.  There's no explanation of what is meant by
canonicalizing spaces.

2. (elisp) `Filling' is OK for NOSQUEEZE: it says that non-nil means to
leave whitespace other than line breaks untouched.  But even that Elisp
doc punts for SQUEEZE-AFTER, saying a position value means "don't
canonicalize spaces before that position."  (That's the only occurrence
of "canonicalize" in this node.  No explanation.)

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor `Microsoft Corp.', version 10.0.19043
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''