better warnings on files that are missing or not normal

aider/repomap.py

@@ -310,7 +310,12 @@ def get_ranked_tags(self, chat_fnames, other_fnames):
         for fname in fnames:
             if not Path(fname).is_file():
                 if fname not in self.warned_files:
-                    self.io.tool_error(f"Repo-map can't include {fname}")
+                    if Path(fname).exists():
+                        self.io.tool_error(
+                            f"Repo-map can't include {fname}, it is not a normal file"
+                        )
+                    else:
+                        self.io.tool_error(f"Repo-map can't include {fname}, it no longer exists")
 
                 self.warned_files.add(fname)
                 continue