Add a bugprone-argument-comment option: IgnoreSingleArgument.

Summary:
Add bugprone-argument-comment option: IgnoreSingleArgument.
When true, the check will ignore the single argument.

Sometimes, it's not necessary to add comment to single argument.
For example:

> std::string name("Yubo Xie");
> pScreen->SetWidth(1920);
> pScreen->SetHeight(1080);

This option can ignore such single argument in bugprone-argument-comment check.

Reviewers: alexfh

Reviewed By: alexfh

Subscribers: cfe-commits

Tags: #clang

Patch by Yubo Xie.

Differential Revision: https://reviews.llvm.org/D67056

llvm-svn: 371075