gh-129842: warnings.py: Remove obsolete requirement reference (GH-129845)

Author: StanFromIreland

Lib/warnings.py

@@ -473,9 +473,6 @@ def __init__(self, *, record=False, module=None,
         """Specify whether to record warnings and if an alternative module
         should be used other than sys.modules['warnings'].
 
-        For compatibility with Python 3.0, please consider all arguments to be
-        keyword-only.
-
         """
         self._record = record
         self._module = sys.modules['warnings'] if module is None else module