Subject: shell-resync-dirs broken on windows

From: Sam Steingold <[email-masked]>
Date: Tue, 26 Mar 2024 12:25:13 -0400

Windows emacs 29.2
Msys2 bash dirs returns something like "/c/foo" for "c:/foo" and
(file-directory-p "/c/foo") returns nil even though "c:/foo" is a directory.
Thus shell-resync-dirs goes into an infinite loop.