The QStringConverter encoding names keys were {{const char*}}s in 6.7, and we recently got a QString overload for them. But these names are only ever used to look stuff up in a lookup table, so this API is a perfect candidate for replacing all of these overload sets with a single QAnyStringView function.

The ICU backend may need to be pessimized a bit, if there's no way to look up an encoding by anything other than a NUL-terminated string (but we can make NUL-termination quicker by using an SSO'ed std::string or QVLA<char>.