Fix for issue #58050
Hi,
a quick PR to mention in the compiler error message that `?` is a macro operator, as according to issue #58050
It passed `python x.py test src/tools/tidy` locally, as well as the recommendation to run `/x.py test src/test/ui --stage 1 --bless`.
Let me know if anything else is needed.
The syntax crate contains those things concerned purely with syntax
– that is, the AST ("abstract syntax tree"), parser, pretty-printer,
lexer, macro expander, and utilities for traversing ASTs.
For more information about how these things work in rustc, see the
rustc guide: