[clangd] Reformat use of cl::opt: use unqualified name and don't bin-pack attributes. NFC

Reviewers: kadircet

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D65154

llvm-svn: 366880