Proposed patch adds re.Patter and re.Match types (names are conforming with the typing module) that represent the types of compiled regular expressin objects and match objects. The purpose of this is exposing the documentation of the methods of these objects in the module documentation produced by pydoc.

The patch also changes the __module__ attribute of these classes and re.error (this enhances the help and repr and increases pickle compatibility of re.error), adds docstrings for re.error and many descriptors, and fixes few other docstrings.