[clang] [clang] [NFC] Comment fix in ParseExpr.cpp (PR #195750)

[A. Jiang via cfe-commits]

frederick-vs-ja wrote:

@vrpT14s I slightly edited the PR message to associate this PR with the related issue. See [GitHub's close/fix/resolve syntax](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue#linking-a-pull-request-to-an-issue-using-a-keyword).

https://github.com/llvm/llvm-project/pull/195750