refactor: Emit deprecation warning when accessing stats instead of …

…`Stats`

src/griffe/stats.py

@@ -2,9 +2,10 @@
 
 from __future__ import annotations
 
+import warnings
 from collections import defaultdict
 from pathlib import Path
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Any
 
 from griffe.enumerations import Kind
 
@@ -13,6 +14,17 @@
     from griffe.loader import GriffeLoader
 
 
+def __getattr__(name: str) -> Any:
+    if name == "stats":
+        warnings.warn(
+            "The 'stats' function was made into a class and renamed 'Stats'.",
+            DeprecationWarning,
+            stacklevel=2,
+        )
+        return Stats
+    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")
+
+
 class Stats:
     """Load statistics for a Griffe loader."""
 
@@ -138,7 +150,4 @@ def as_text(self) -> str:
         return "\n".join(lines)
 
 
-stats = Stats
-"""Deprecated. Use `Stats` instead."""
-
 __all__ = ["Stats"]