Docstring fixes

This change addresses all but three docstring format issues.
Not all missing docstrings have been added.

- Colons added in @param and @type.
- Replaced 'pywikibot.Claim' with 'Claim' in @type.

Change-Id: I83a1a672de9415a9fbc3baab906cee78e85a44b9
Merge "Docstring fixes"