bug#73954: 30.0.91; Don't hard-couple `dired-hide-details-hide-absolute-location' with `dired-hide-details-mode'

[Drew Adams via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

Starting with Emacs 30 Dired directory header lines apparently show
relative names when `dired-hide-details-mode' is on, if option
`dired-hide-details-hide-absolute-location' is non-nil.

(The only Windows v30 pretest snapshot I found doesn't have this option,
so I'm going only by the description from bug #72272.)

The behavior of being able to show only a relative name is a good one,
but it shouldn't be hard-coupled with `dired-hide-details-mode'.  Users
should be able to choose:

 nil                         Always show absolute name.
                             (This needs to stay the default.) 
 if-dired-hide-details-mode  Show relative name only when
                             `dired-hide-details-mode' is on.
 t                           Always show relative name.
 FUNCTION                    Show relative name only when invoking
                             FUNCTION with no args returns non-nil.

The most important behaviors are for nil, t, and
`if-hiding-detail-columns'.  FUNCTION is a nice-to-have.

(An alternative would be to use t for showing relative name when
`dired-hide-details-mode' is on and `always' for showing relative names
always.  That keeps the current pre-release behavior for t.  I don't
think it's preferable, but it's a possibility.)


In GNU Emacs 30.0.91 (build 2, x86_64-w64-mingw32) of 2024-09-11 built
 on AVALON
Windowing system distributor 'Microsoft Corp.', version 10.0.19045
System Description: Microsoft Windows 10 Pro (v10.0.2009.19045.5011)

Configured using:
 'configure --with-modules --without-dbus --with-native-compilation=aot
 --without-compress-install --with-tree-sitter
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -g3''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG LCMS2 LIBXML2 MODULES NATIVE_COMP
NOTIFY W32NOTIFY PDUMPER PNG RSVG SOUND SQLITE3 THREADS TIFF
TOOLKIT_SCROLL_BARS TREE_SITTER WEBP XPM ZLIB

(NATIVE_COMP present but libgccjit not available)

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1252