Few more fixes for issues found by testing on internal codebases (#4876)

Few unrelated (but quite obvious) fixes here.

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stdlib/2and3/xml/dom/minidom.pyi

@@ -1,6 +1,6 @@
-from typing import Any, Optional
+from typing import Any, Optional, Text, Union
 from xml.sax.xmlreader import XMLReader
 
 def parse(file: str, parser: Optional[XMLReader] = ..., bufsize: Optional[int] = ...): ...
-def parseString(string: str, parser: Optional[XMLReader] = ...): ...
+def parseString(string: Union[bytes, Text], parser: Optional[XMLReader] = ...): ...
 def __getattr__(name: str) -> Any: ...  # incomplete