Fix spellcheck error on head of f/prefixed strings

[kfollstad]

Fixes #43

[kfollstad]

Fixes #47 as well. My initial commits only implemented the pythonQuotes group, which fulfilled @sscherfke's request, but not @qwenger's. On the last commit (40dbae2) I substituted pythonTripleQuotes where appropriate to match upstream. Hopefully this helps remove a barrier to getting some of these ideas adopted by upstream (which was mentioned in another issue as something that might be desirable).

[qsantos]

I confirm this fixes my problem (#43).