resetwarnings(): Remove extra space from docstring guts.

Lib/warnings.py

@@ -139,7 +139,7 @@ def filterwarnings(action, message="", category=Warning, module="", lineno=0,
         filters.insert(0, item)
 
 def resetwarnings():
-    """Clear the list of warning filters, so that  no filters are active."""
+    """Clear the list of warning filters, so that no filters are active."""
     filters[:] = []
 
 class _OptionError(Exception):