(fix): caching symlinked files (#2112)

* Revert "(fix): `org-roam-descendant-of-p` bug on Windows (#2089)"

This reverts commit 97a342fd3f.

Reason:

It seems that the `file-in-directory-p` function proposed in #2089 is provided only for
*physical directories*, does not work as we would like with *symlinked directories*.
It dereferences all the symlinks in its path, and previously seemed related paths
cease to be such.

Because of this, such notes are ignored and not indexed, although they
were indexed earlier.

org-roam-utils.el

@@ -108,6 +108,13 @@ SPEC is a list, as per `dolist'."
       `(dolist-with-progress-reporter ,spec ,msg ,@body)
     `(dolist ,spec ,@body)))
 
+;;; File utilities
+(defun org-roam-descendant-of-p (a b)
+  "Return t if A is descendant of B."
+  (unless (equal (file-truename a) (file-truename b))
+    (string-prefix-p (replace-regexp-in-string "^\\([A-Za-z]\\):" 'downcase (expand-file-name b) t t)
+                     (replace-regexp-in-string "^\\([A-Za-z]\\):" 'downcase (expand-file-name a) t t))))
+
 (defmacro org-roam-with-file (file keep-buf-p &rest body)
   "Execute BODY within FILE.
 If FILE is nil, execute BODY in the current buffer.