Auto merge of #33311 - birkenfeld:issue33262, r=nrc

parser: fix suppression of syntax errors in range RHS

Invalid expressions on the RHS were just swallowed without generating an error.  The new version more closely mirrors the code for parsing `..x` in the `parse_prefix_range_expr` method below, where no cancel is done either.

Fixes #33262.

diff --cc src/libsyntax/parse/parser.rs
Simple merge