[clangd] Highlighting auto variables as the deduced type.

Summary:
Done in VisitDeclaratorDecl as the AutoTypeLoc is not deduced.
Scoped to only work for variables.
auto function return values need to be handled in a special way (separate patch for that).
auto's that are in lambdas ar enot highlighted as we don't highlight their underlying type (it's a RecordDecl, but the name is not an identifier so it returns in addToken).

Reviewers: hokein, ilya-biryukov

Subscribers: MaskRay, jkorous, arphaman, kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65996

git-svn-id: https://llvm.org/svn/llvm-project/clang-tools-extra/trunk@368546 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed