Point at all the unnecessary trailing `#`.
Better handle interaction with outer attributes when `;` is missing.

Fix rust-lang#95030.

In rust-lang#96303, I changed the tests not to manage submodules, with the main
goal of avoiding a clone for llvm-project. Unfortunately, there are some tests
which depend on submodules - I didn't notice locally because they were already checked out for me,
and CI doesn't use submodule handling at all. Fresh clones, however, were impacted:
```
failures:

---- builder::tests::defaults::doc_default stdout ----
thread 'main' panicked at 'fs::read_dir(builder.src.join(&relative_path).join("redirects")) failed with No such file or directory (os error 2)', src/bootstrap/doc.rs:232:21
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- builder::tests::dist::dist_only_cross_host stdout ----
thread 'main' panicked at 'fs::read_to_string(&toml_file_name) failed with No such file or directory (os error 2)', src/bootstrap/lib.rs:1314:20
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

Try and get the best of both worlds by only checking out the submodules actually used in tests.

…=Manishearth

Add more diagnostic items

This just adds a handful diagnostic items I noticed were missing.

Would it be worth doing this for all of the remaining types? I'm willing to do it if it'd be helpful.

…rors

Better handle too many `#` recovery in raw str

Point at all the unnecessary trailing `#`.
Better handle interaction with outer attributes when `;` is missing.

Fix rust-lang#95030.

Switch JS code to ES6

Considering it's already quite big, I'll do the remaining files in another PR.

Part of rust-lang#93058.

r? ```@notriddle```

…-Simulacrum

Fix running bootstrap tests on a fresh clone

In rust-lang#96303, I changed the tests not to manage submodules, with the main
goal of avoiding a clone for llvm-project. Unfortunately, there are some tests
which depend on submodules - I didn't notice locally because they were already checked out for me,
and CI doesn't use submodule handling at all. Fresh clones, however, were impacted:
```
failures:

---- builder::tests::defaults::doc_default stdout ----
thread 'main' panicked at 'fs::read_dir(builder.src.join(&relative_path).join("redirects")) failed with No such file or directory (os error 2)', src/bootstrap/doc.rs:232:21
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

---- builder::tests::dist::dist_only_cross_host stdout ----
thread 'main' panicked at 'fs::read_to_string(&toml_file_name) failed with No such file or directory (os error 2)', src/bootstrap/lib.rs:1314:20
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
```

Try and get the best of both worlds by only checking out the submodules actually used in tests.

…-errors

delay bug when adjusting `NeverToAny` twice during diagnostic code

Addresses Issue 96335 (rust-lang#96335) by using `delay_span_bug` instead of an assert and returning an error type from `check_expr_meets_expectation_or_error`.

Fixes rust-lang#96335

…er-errors

do not consider two extern types to be similar