[clang-tools-extra] [clang-tidy][abseil-string-find-startswith] Add string_view to default string-like classes (PR #72283)

[Nicolas van Kempen via cfe-commits]

nicovank wrote:

> Copy this check.

Got it. Thanks for the pointer!

> Documentation, string header.

I think I covered everything, had to add a couple of skeletons to that `string` common header.

https://github.com/llvm/llvm-project/pull/72283