10642: minor: Add dummy impls for `trace_macros` and `log_syntax` r=Veykril a=Veykril
Both of these are macros for debugging macros and as such don't really need an implementation for us.
Closes https://github.com/rust-analyzer/rust-analyzer/issues/2212
bors r+
Co-authored-by: Lukas Wirth <lukastw97@gmail.com>