[clang] [clang-tools-extra] [clang] skip explicit obj param in code complete (PR #146258)

[Nathan Ridge via cfe-commits]

https://github.com/HighCommander4 approved this pull request.

The new test + other updates look great, thanks!

I agree with using the terminology "explicit object parameter", as this is what appears in the clang API (e.g. `ParmVarDecl::isExplicitObjectParameter()`).

@MythreyaK I'll hold off on merging this until I get a confirmation from you (since the patch is still currently in the "Draft" state), but from my point of view this is good to go.

https://github.com/llvm/llvm-project/pull/146258