Make a couple of useful typo correction callbacks more widely available.
Attempt typo correction for function calls with the wrong number of arguments.

Combined with typo correction's new ability to apply global/absolute nested
name specifiers to possible corrections, cases such as in PR12287 where the
desired function is being shadowed by a lexically closer function with the
same name but a different number of parameters will now include a FixIt.

On a side note, since the test for this change caused
test/SemaCXX/typo-correction.cpp to exceed the typo correction limit for
a single file, I've included a test case for exceeding the limit and added
some comments to both the original and part two of typo-correction.cpp
warning future editors of the files about the limit.