[clangd] Prefer the left character if the character on the right of the cursor is semicolon.

Summary: This would make go-to-def works on the cases like int A = abc^;

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D70807