add captureWarnings to stdlib logging (#1298)

Fixes #1235

stdlib/2and3/logging/__init__.pyi

@@ -345,6 +345,9 @@ else:
 def shutdown() -> None: ...
 
 def setLoggerClass(klass: type) -> None: ...
+
+def captureWarnings(capture: bool) -> None: ...
+
 if sys.version_info >= (3,):
     def setLogRecordFactory(factory: Callable[..., LogRecord]) -> None: ...