Regexp-quote github domains in bug-reference

* lisp/progmodes/bug-reference.el
(bug-reference--build-forge-setup-entry): Regexp-quote the domain
(bug#51316).

lisp/progmodes/bug-reference.el

@@ -270,7 +270,8 @@ via the internet it might also be http.")
 ;; possibly different projects are also supported.
 (cl-defmethod bug-reference--build-forge-setup-entry
   (host-domain (_forge-type (eql github)) protocol)
-  `(,(concat "[/@]" host-domain "[/:]\\([.A-Za-z0-9_/-]+\\)\\.git")
+  `(,(concat "[/@]" (regexp-quote host-domain)
+             "[/:]\\([.A-Za-z0-9_/-]+\\)\\.git")
     "\\(\\([.A-Za-z0-9_/-]+\\)?\\(?:#\\)\\([0-9]+\\)\\)\\>"
     ,(lambda (groups)
        (let ((ns-project (nth 1 groups)))