[clang-format] Formatter does not handle c++11 string literal prefix with stringize #

https://github.com/llvm/llvm-project/issues/27740

Ensure
```
```
behave the same as
```
```

when formatted, ensure clang-format follows the conventions for `L` `u` `U` `u8`

https://docs.microsoft.com/en-us/cpp/cpp/string-and-character-literals-cpp?redirectedfrom=MSDN&view=msvc-170

Fixes #27740

Reviewed By: curdeius, owenpan

Differential Revision: https://reviews.llvm.org/D115938