isdir.m: Make m-file a legacy function (bug #54489) * isdir.m: Note that function is not recommended in docstring. Add 1-time warning about function being obsolete. Add first time BIST test to provoke and suppress warning. * scripts/legacy/module.mk, scripts/miscellaneous/module.mk: Move isdir.m from miscellaneous/ dir to legacy/ dir. * NEWS: Announce change to legacy function. * syscalls.cc (Fstat): Add isfolder to @seealso link. * utils.cc (Fis_absolute_filename, Fis_rooted_relative_filename, Fmake_absolute_filename): Replace isdir with isfolder in @seealso links. * uigetdir.m, uigetfile.m, uiputfile.m, which.m, copyfile.m, mkdir.m, movefile.m, tempdir.m, unpack.m, what.m, __print_parse_opts__.m, compare_plot_demos.m, rundemos.m, runtests.m: Replace instances of isdir with isfolder in core Octave.

FCN_FILE_DIRS += scripts/legacy

%canon_reldir%_FCN_FILES = \
  %reldir%/findstr.m \
  %reldir%/flipdim.m \
  %reldir%/isdir.m \
  %reldir%/isequalwithequalnans.m \
  %reldir%/isstr.m \
  %reldir%/setstr.m \
  %reldir%/strmatch.m \
  %reldir%/strread.m \
  %reldir%/textread.m

%canon_reldir%dir = $(fcnfiledir)/legacy

%canon_reldir%_DATA = $(%canon_reldir%_FCN_FILES)

FCN_FILES += $(%canon_reldir%_FCN_FILES)

PKG_ADD_FILES += %reldir%/PKG_ADD

DIRSTAMP_FILES += %reldir%/$(octave_dirstamp)