clarify reference symlink validation error

Author: codex

git/refs/symbolic.py

@@ -120,7 +120,7 @@ def _get_validated_path(base: PathLike, path: PathLike) -> str:
                 continue
             cur_path = os.path.join(cur_path, part)
             if os.path.islink(cur_path):
-                raise ValueError("Reference path %r escapes the repository" % path)
+                raise ValueError("Reference path %r includes a symlink component" % path)
         abs_path = os.path.realpath(os.path.join(base_path, path))
         try:
             common_path = os.path.commonpath([base_path, abs_path])