ambrevar/file: Add path defmethod for strings and pathnames.

.local/share/common-lisp/source/ambrevar/file.lisp

@@ -45,6 +45,12 @@
     (:export-accessor-names-p t)
     (:export-class-name-p t))
 
+(defmethod path ((s string))
+  s)
+
+(defmethod path ((p pathname))
+  (namestring p))
+
 (export-always 'extension)
 (defmethod extension ((file file))
   "Return the file extension.