Use project.el for default search

`rgrep` can be used when `project-find-regexp` does not find matches, but the latter can be used
more intuitively and also provides choosing the base directory and a file pattern via universal
arguments.

init.el

@@ -3021,7 +3021,7 @@ eventuelly be set to nil, however)."
   (bind-key "<Scroll_Lock>" 'scroll-lock-mode)
   (bind-key "<f1>" #'db/run-or-hide-eshell)
   (bind-key "<f2>" #'hydra-feature-shortcuts/body)
-  (bind-key "<f5>" #'rgrep)
+  (bind-key "<f5>" #'project-find-regexp)
   (bind-key "<f6>" #'hydra-zoom/body)
   (bind-key "<f7>" #'dictcc)
   (bind-key "<f9>" #'hydra-org-linking/body)