Today, there's Find(), FindIgnoringASCII(), and FindIgnoringCase(). Find() also takes an optional enum argument that controls case-sensitivity of matching.

However, Contains(), StartsWith(), and EndsWith() don't have any equivalents of the IgnoringASCIICase() and IgnoringCase() versions. We should add them for consistency, switch code to use them, and see if we can even remove the enum argument from Find(), so that we can name Find() identically to std::string::find.