fix: Increase stash key length from 1 to 2

Cross-reference stash keys start with `_` and preserve the rendered identifier length. One-character and two-character identifiers therefore share a keyspace of only 62 keys. Once all keys are present, `_gen_stash_key` retries random choices forever. This happens for example in mkdocstrings when rendering an attribute value that has 62 names in it or more. We increase the minimum key length by 1, to reach a keyspace of 3844, making it very unlikely to hit the limit again.

PR-336: #336

Author: jonashaag

src/mkdocstrings_handlers/python/_internal/rendering.py

@@ -107,7 +107,7 @@ class _StashCrossRefFilter:
 
     @staticmethod
     def _gen_key(length: int) -> str:
-        return "_" + "".join(random.choice(string.ascii_letters + string.digits) for _ in range(max(1, length - 1)))  # noqa: S311
+        return "_" + "".join(random.choice(string.ascii_letters + string.digits) for _ in range(max(2, length - 1)))  # noqa: S311
 
     def _gen_stash_key(self, length: int) -> str:
         key = self._gen_key(length)