Remove git.util.NullHandler

git.util has an __all__ attribute, which does not list NullHandler.
As NullHandler is not otherwise documented to be public, removing
it is not a breaking change, and there is no need for a deprecation
period or to wait until the next major version of GitPython.

See 741dfd3 for information about its history.

Author: EliahKagan

Diff for: git/util.py

@@ -1292,23 +1292,3 @@ def list_items(cls, repo: "Repo", *args: Any, **kwargs: Any) -> Any:
 
 
 # } END classes
-
-
-class NullHandler(logging.Handler):
-    """Deprecated, use :class:`logging.NullHandler` instead.
-
-    This noop handler is like :class:`~logging.NullHandler` in the standard library,
-    which should be used instead, because it is now always available, and it overrides
-    more logging methods to make them noop. This class only overrides :meth:`emit`.
-    """
-
-    def __init__(self, level: int = logging.NOTSET) -> None:
-        warnings.warn(
-            "NullHandler in git.util is deprecated. Use logging.NullHandler instead.",
-            DeprecationWarning,
-            stacklevel=2,
-        )
-        super().__init__(level)
-
-    def emit(self, record: logging.LogRecord) -> None:
-        pass