Rollup merge of #114228 - fmease:wf-lazy-ty-aliases, r=oli-obk

Check lazy type aliases for well-formedness

Previously we didn't check if `T: Mul` holds given lazy `type Alias<T> = <T as Mul>::Output;`.
Now we do. It only makes sense.

`@rustbot` label F-lazy_type_alias

r? `@oli-obk`

src/tools/tidy/src/ui_tests.rs

@@ -11,7 +11,7 @@ use std::path::{Path, PathBuf};
 const ENTRY_LIMIT: usize = 900;
 // FIXME: The following limits should be reduced eventually.
 const ISSUES_ENTRY_LIMIT: usize = 1893;
-const ROOT_ENTRY_LIMIT: usize = 872;
+const ROOT_ENTRY_LIMIT: usize = 873;
 
 const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
     "rs",     // test source files