Merge pull request matplotlib#26940 from hhoppe/hhoppe-patch-1

Add typing to pyplot.show() to avoid errors with mypy --strict.

Author: timhoffm

lib/matplotlib/pyplot.py

@@ -478,7 +478,7 @@ def draw_if_interactive(*args, **kwargs):
 
 
 # This function's signature is rewritten upon backend-load by switch_backend.
-def show(*args, **kwargs):
+def show(*args, **kwargs) -> None:
     """
     Display all open figures.