[clang] [Clang] omit parentheses in fold expressions with a single expansion (PR #110761)

[via cfe-commits]

cor3ntin wrote:

I am happy with the direction, but I think we need changes to ASTStmtReader::VisitParenExpr/ASTStmtWriter::VisitParenExpr

(also, I want to make sure Erich is happy too)

https://github.com/llvm/llvm-project/pull/110761