…eGomez

Make `Clean` take &mut DocContext

- Take `FnMut` in `rustc_trait_selection::find_auto_trait_generics`
- Take `&mut DocContext` in most of `clean`
- Collect the iterator in auto_trait_impls instead of iterating lazily; the lifetimes were really bad.

This combined with rust-lang#82018 should hopefully help with rust-lang#82014 by allowing `cx.cache.exported_traits` to be modified in `register_res`. Previously it had to use interior mutability, which required either adding a RefCell to `cache.exported_traits` on *top* of the existing `RefCell<Cache>` or mixing reads and writes between `cx.exported_traits` and `cx.cache.exported_traits`. I don't currently have that working but I expect it to be reasonably easy to add after this.

…laumeGomez

Rollup of 7 pull requests

Successful merges:

 - rust-lang#80734 (check that first arg to `panic!()` in const is `&str`)
 - rust-lang#81932 (Always compile rustdoc with debug logging enabled when `download-rustc` is set)
 - rust-lang#82018 (Remove the dummy cache in `DocContext`; delete RenderInfo)
 - rust-lang#82598 (Check stability and feature attributes in rustdoc)
 - rust-lang#82655 (Highlight identifier span instead of whole pattern span in `unused` lint)
 - rust-lang#82662 (Warn about unknown doc attributes)
 - rust-lang#82676 (Change twice used large const table to static)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

…laumeGomez

Remove RefCell around `module_trait_cache`

This builds on rust-lang#82018 and should not be merged before.

## Don't require a `DocContext` for `report_diagnostic`

This is needed for the next commit, which needs mutable access to the `cx` from
within the `decorate` closure.

- Change `as_local_hir_id` to an associated function, since it only
  needs a `TyCtxt`
- Change `source_span_for_markdown_range` to only take a `TyCtxt`

##  Remove RefCell around module_trait_cache

This is mostly just changing lots of functions from `&DocContext` to `&mut DocContext`.

…laumeGomez

Remove RefCell around `module_trait_cache`

This builds on rust-lang#82018 and should not be merged before.

## Don't require a `DocContext` for `report_diagnostic`

This is needed for the next commit, which needs mutable access to the `cx` from
within the `decorate` closure.

- Change `as_local_hir_id` to an associated function, since it only
  needs a `TyCtxt`
- Change `source_span_for_markdown_range` to only take a `TyCtxt`

##  Remove RefCell around module_trait_cache

This is mostly just changing lots of functions from `&DocContext` to `&mut DocContext`.

…laumeGomez

Remove RefCell around `module_trait_cache`

This builds on rust-lang#82018 and should not be merged before.

## Don't require a `DocContext` for `report_diagnostic`

This is needed for the next commit, which needs mutable access to the `cx` from
within the `decorate` closure.

- Change `as_local_hir_id` to an associated function, since it only
  needs a `TyCtxt`
- Change `source_span_for_markdown_range` to only take a `TyCtxt`

##  Remove RefCell around module_trait_cache

This is mostly just changing lots of functions from `&DocContext` to `&mut DocContext`.

…laumeGomez

Remove RefCell around `module_trait_cache`

This builds on rust-lang#82018 and should not be merged before.

## Don't require a `DocContext` for `report_diagnostic`

This is needed for the next commit, which needs mutable access to the `cx` from
within the `decorate` closure.

- Change `as_local_hir_id` to an associated function, since it only
  needs a `TyCtxt`
- Change `source_span_for_markdown_range` to only take a `TyCtxt`

##  Remove RefCell around module_trait_cache

This is mostly just changing lots of functions from `&DocContext` to `&mut DocContext`.

…laumeGomez

Remove RefCell around `module_trait_cache`

This builds on rust-lang#82018 and should not be merged before.

## Don't require a `DocContext` for `report_diagnostic`

This is needed for the next commit, which needs mutable access to the `cx` from
within the `decorate` closure.

- Change `as_local_hir_id` to an associated function, since it only
  needs a `TyCtxt`
- Change `source_span_for_markdown_range` to only take a `TyCtxt`

##  Remove RefCell around module_trait_cache

This is mostly just changing lots of functions from `&DocContext` to `&mut DocContext`.

Remove `masked_crates` from `clean::Crate`

Previously, `masked_crates` existed both on `Cache` and on
`clean::Crate`. During cache population, the `clean::Crate` version was
`take`n and moved to `Cache`.

This change removes the version on `clean::Crate` and instead directly
mutates `Cache.masked_crates` to initialize it. This has the advantage
of avoiding duplication and avoiding unnecessary allocation, as well as
making the flow of information through rustdoc less confusing.

The one downside I see is that `clean::utils::krate()` now uses the side
effect of mutating `DocContext.cache` instead of returning the data
directly, but it already mutated the `Cache` for other things (e.g.,
`deref_trait_did`) so it's not really new behavior. Also,
`clean::utils::krate()` is only called once (and is meant to only be
called once since it performs expensive and potentially destructive
operations) so the mutation shouldn't be an issue.

Follow-up to rust-lang#82018 (comment).

cc `@jyn514`