Rollup merge of #83216 - jyn514:register-tool, r=petrochenkov

Allow registering tool lints with `register_tool`

Previously, there was no way to add a custom tool prefix, even if the tool
itself had registered a lint:

 ```rust
 #![feature(register_tool)]
 #![register_tool(xyz)]
 #![warn(xyz::my_lint)]
 ```

```
$ rustc unknown-lint.rs  --crate-type lib
error[E0710]: an unknown tool name found in scoped lint: `xyz::my_lint`
 --> unknown-lint.rs:3:9
  |
3 | #![warn(xyz::my_lint)]
  |         ^^^
```

This allows opting-in to lints from other tools using `register_tool`.

cc https://github.com/rust-lang/rust/issues/66079#issuecomment-788589193, ``@chorman0773``
r? ``@petrochenkov``

compiler/rustc_lint/src/context.rs

@@ -748,7 +748,7 @@ impl<'a> EarlyContext<'a> {
             sess,
             krate,
             lint_store,
-            builder: LintLevelsBuilder::new(sess, warn_about_weird_lints, lint_store),
+            builder: LintLevelsBuilder::new(sess, warn_about_weird_lints, lint_store, &krate.attrs),
             buffered,
         }
     }