[clangd] Fix crash in applyTweak, remove TweakID alias.

Strings are complicated, giving them opaque names makes us forget
they're complicated.

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@352837 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed