abseil-string-find-str-contains should not propose an edit for the...

abseil-string-find-str-contains should not propose an edit for the three-parameter version of find().

std::string, std::string_view, and absl::string_view all have a three-parameter version of find()
which has a "count" (or "n") paremeter limiting the size of the substring to search.  We don't want
to propose changing to absl::StrContains in those cases.  This change fixes that and adds unit tests
to confirm.

Reviewed By: ymandel

Differential Revision: https://reviews.llvm.org/D107837