Fix typing annotations for get_parameters_overview

PiperOrigin-RevId: 612454326

Author: Conchylicultor

clu/parameter_overview.py

@@ -259,15 +259,17 @@ def _get_parameter_overview(
 def get_parameter_overview(
     params: _ParamsContainer,
     *,
-    include_stats: bool = True,
+    include_stats: bool | str = True,
     max_lines: int | None = None,
 ) -> str:
   """Returns a string with variables names, their shapes, count.
 
   Args:
     params: Dictionary with parameters as NumPy arrays. The dictionary can be
       nested.
-    include_stats: If True, add columns with mean and std for each variable.
+    include_stats: If True, add columns with mean and std for each variable. If
+      the string "global", params are sharded global arrays and this function
+      assumes it is called on every host, i.e. can use collectives.
     max_lines: If not `None`, the maximum number of variables to include.
 
   Returns: