Stop compilation early if macro expansion failed
Fixesrust-lang/rust#116180.
So there isn't really a type that is central for macro expansion and some errors are actually emitted (because the resolution happens after the expansion I suppose) after the expansion pass (like "not found macro"). Sometimes, errors are only emitted on the second "try" (to improve error output). So I couldn't reach a similar solution than what was done in https://github.com/rust-lang/rust/pull/133937 and suggested by ````@estebank```` in https://github.com/rust-lang/rust/issues/116180#issuecomment-3109468922. But maybe I missed something?
So in the end, I realized that there is method called every time (except one, described below) a macro error is actually emitted: `ExtCtxt::trace_macros_diag`. Considering I updated what it did, I renamed it into `macro_error_and_trace_macros_diag` to better reflect it.
There is only one call of `trace_macros_diag` which isn't reporting an error but just used for `macro_trace` feature, so I kept it as is.
r? ````@oli-obk````
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