Suggest public re-exports when a private module makes an import path inaccessible

This is an attempt at solving rust-lang#13065.

When a `use` path fails because it passes through a private module (E0603), and a public re-export of the target item exists elsewhere, the compiler will now suggest importing through that re-export instead.

For example, given:

```rust
mod outer {
    pub use self::inner::MyStruct;
    mod inner {
        pub struct MyStruct;
    }
}

use outer::inner::MyStruct; // error: module `inner` is private
```

the compiler will now suggest use `outer::MyStruct`; - the publicly accessible path - rather than just pointing at the private module definition and leaving the user to figure out the alternative.

When possible, relative paths are suggested, including those using `super` (currently capped at a maximum of one `super` path item).

The newly added test is parametrised by editions because of the change in behaviour around `crate::`-prefixed imports in edition 2018. Perhaps that’s an overkill – I’ll be happy to remove the variations for editions 2021 and 2024.

Closes rust-lang#13065.

…uwer

Rollup of 13 pull requests

Successful merges:

 - #155249 (Fix: On wasm targets, call `panic_in_cleanup` if panic occurs in cleanup)
 - #155853 (Use `_mcount` as the mcount symbol name on RISC-V Linux GNU targets)
 - #155919 (simplify `ast_fragments!`)
 - #155939 (Add feature gate for view_types experiment)
 - #155974 (add `c_variadic_experimental_arch` feature)
 - #155991 (Catch unwinds from the global ctxt callback to complete queries profiling data in more cases)
 - #156003 (Pass Session to optimize_and_codegen_fat_lto)
 - #153566 (Add suggestion for E0401 on inner const items)
 - #154610 (Suggest public re-exports when a private module makes an import path inaccessible)
 - #155523 (Reorganize `tests/ui/issues/` - 02)
 - #155980 (Move `feature*` methods from `parse` mod to `errors` mod.)
 - #155987 (Make lifting infallible)
 - #155988 (tests/run-make/print-cfg: add Android target_env case)

Rollup of 19 pull requests

Successful merges:

 - #155237 (Disentangle AST crates and error crates)
 - #155249 (Fix: On wasm targets, call `panic_in_cleanup` if panic occurs in cleanup)
 - #155853 (Use `_mcount` as the mcount symbol name on RISC-V Linux GNU targets)
 - #155919 (simplify `ast_fragments!`)
 - #155939 (Add feature gate for view_types experiment)
 - #155954 (rustdoc: preserve parent doc cfg for `macro_export` macros)
 - #155974 (add `c_variadic_experimental_arch` feature)
 - #155991 (Catch unwinds from the global ctxt callback to complete queries profiling data in more cases)
 - #156003 (Pass Session to optimize_and_codegen_fat_lto)
 - #153566 (Add suggestion for E0401 on inner const items)
 - #154610 (Suggest public re-exports when a private module makes an import path inaccessible)
 - #155523 (Reorganize `tests/ui/issues/` - 02)
 - #155821 (c-variadic: document `Clone` and `Drop` instances and require `VaArgSafe: Copy`)
 - #155980 (Move `feature*` methods from `parse` mod to `errors` mod.)
 - #155987 (Make lifting infallible)
 - #155988 (tests/run-make/print-cfg: add Android target_env case)
 - #156000 (Fix ICE when using -Zinstrument-mcount and -Clinker-flavor=lld)
 - #156002 (Allow to use `Diagnostic` directly in `SharedContext::emit_lint`)
 - #156015 (rustc-dev-guide subtree update)

Rollup merge of #154610 - jakubadamw:issue-13065, r=TaKO8Ki

Suggest public re-exports when a private module makes an import path inaccessible

This is an attempt at solving #13065.

When a `use` path fails because it passes through a private module (E0603), and a public re-export of the target item exists elsewhere, the compiler will now suggest importing through that re-export instead.

For example, given:

```rust
mod outer {
    pub use self::inner::MyStruct;
    mod inner {
        pub struct MyStruct;
    }
}

use outer::inner::MyStruct; // error: module `inner` is private
```

the compiler will now suggest use `outer::MyStruct`; - the publicly accessible path - rather than just pointing at the private module definition and leaving the user to figure out the alternative.

When possible, relative paths are suggested, including those using `super` (currently capped at a maximum of one `super` path item).

The newly added test is parametrised by editions because of the change in behaviour around `crate::`-prefixed imports in edition 2018. Perhaps that’s an overkill – I’ll be happy to remove the variations for editions 2021 and 2024.

Closes #13065.

Rollup of 19 pull requests

Successful merges:

 - rust-lang/rust#155237 (Disentangle AST crates and error crates)
 - rust-lang/rust#155249 (Fix: On wasm targets, call `panic_in_cleanup` if panic occurs in cleanup)
 - rust-lang/rust#155853 (Use `_mcount` as the mcount symbol name on RISC-V Linux GNU targets)
 - rust-lang/rust#155919 (simplify `ast_fragments!`)
 - rust-lang/rust#155939 (Add feature gate for view_types experiment)
 - rust-lang/rust#155954 (rustdoc: preserve parent doc cfg for `macro_export` macros)
 - rust-lang/rust#155974 (add `c_variadic_experimental_arch` feature)
 - rust-lang/rust#155991 (Catch unwinds from the global ctxt callback to complete queries profiling data in more cases)
 - rust-lang/rust#156003 (Pass Session to optimize_and_codegen_fat_lto)
 - rust-lang/rust#153566 (Add suggestion for E0401 on inner const items)
 - rust-lang/rust#154610 (Suggest public re-exports when a private module makes an import path inaccessible)
 - rust-lang/rust#155523 (Reorganize `tests/ui/issues/` - 02)
 - rust-lang/rust#155821 (c-variadic: document `Clone` and `Drop` instances and require `VaArgSafe: Copy`)
 - rust-lang/rust#155980 (Move `feature*` methods from `parse` mod to `errors` mod.)
 - rust-lang/rust#155987 (Make lifting infallible)
 - rust-lang/rust#155988 (tests/run-make/print-cfg: add Android target_env case)
 - rust-lang/rust#156000 (Fix ICE when using -Zinstrument-mcount and -Clinker-flavor=lld)
 - rust-lang/rust#156002 (Allow to use `Diagnostic` directly in `SharedContext::emit_lint`)
 - rust-lang/rust#156015 (rustc-dev-guide subtree update)