Changes

[clangd] Do not highlight keywords in semantic highlighting
Summary: Editors are good at highlightings the keywords themselves. Note
that this only affects highlightings of builtin types spelled out as
keywords in the source code. Highlightings of typedefs to builtin types
are unchanged.
Reviewers: hokein
Reviewed By: hokein
Subscribers: merge_guards_bot, MaskRay, jkorous, arphaman, kadircet,
usaxena95, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D69431