GitLab

* lisp/minibuffer.el (completion-category-defaults):
Add `project-file' category.

* lisp/progmodes/project.el (project-find-file)
(project-or-external-find-file): New commands.
(project--find-file-in): New private function.

* lisp/progmodes/xref.el (xref-collect-matches): Use
`expand-file-name' on DIR, to expand the tildes.
(xref--find-ignores-arguments): Extract from
`xref--rgrep-command'.