bug#52339: 26.3; Doc of functions that accept file-name args: say whether absolute

[Drew Adams]

This report is about the doc strings and the doc in the Elisp manual for
functions that accept file-name args.

Please say, somewhere (preferably in each relevant node, since someone
might not start reading in node `Information about Files'), about the
file-name arg for a function documented in the node, whether the name
must be absolute or relative (e.g. to `default-directory') or can be
either.  Similarly, for the doc strings of such functions.

E.g. function `file-exists-p' itself expands its arg relative to
`default-directory', if the arg isn't an absolute name.  This isn't
obvious.

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor `Microsoft Corp.', version 10.0.19042
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''