[clang] [clang] Improve diagnostics for invalid named-universal-characters (PR #206326)

[Jan Schultke via cfe-commits]

eisenwave wrote:

CC @cor3ntin

This pulls all the remaining fixes out of #203944, without actually implementing support for abbreviations and figments.

In the example with `"\N{🤡}"`, no fix suggestions are offered anymore because it would just be low-quality garbage suggestions anyway. The bigger issue for the user to fix is that they are using illegal characters in the name, so they should probably focus on that first.


https://github.com/llvm/llvm-project/pull/206326