Auto merge of #104875 - chenyukang:yukang/fix-104867-inc, r=estebank

Properly handle postfix inc/dec in standalone and subexpr scenarios

Fixes #104867
r? `@estebank`

diff --cc compiler/rustc_parse/src/parser/diagnostics.rs
Simple merge

diff --cc compiler/rustc_parse/src/parser/expr.rs
Simple merge

diff --cc compiler/rustc_parse/src/parser/stmt.rs
Simple merge