GDB 11.2 added support for DW_ATE_UTF, which caused some test
failures.  This fixes these tests by changing the format that is used,
and adds a new test to verify that characters are emitted as something
that GDB can print in a char-like way.

Fixes rust-lang#94458

I thought that the documentation for these methods needed to be a bit more explanatory for new users. For advanced users, the comments are relatively unnecessary. I think it would be useful to explain precisely what the method does. As a new user, when you see the `into` method, where the type is inferred, if you are new you don't even know what you convert to, because it is implicit. I believe this can help new users understand.

Made because I was making a code change and got a very confusing "should be applied to a method, not a method" error.

```
error[E0718]: `into_try_type` language item must be applied to a method
   --> library\core\src\ops\try_trait.rs:352:32
    |
352 |     #[cfg_attr(not(bootstrap), lang = "into_try_type")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^ attribute should be applied to a method, not a method
```

It is UB for LLVM and results in a compile error for Cranelift

…crum

Update libc to 0.2.121

Updating libc to 0.2.119 adds platform support for m68k-unknown-linux-gnu.

Fix diagnostics for `#![feature(deprecated_suggestion)]`

Follow up from rust-lang#94635, where I missed a couple things.

…an-DPC

Add Stream alias for AsyncIterator

Fixes rust-lang#94965

…imulacrum

Fix debuginfo tests with GDB 11.2

GDB 11.2 added support for DW_ATE_UTF, which caused some test
failures.  This fixes these tests by changing the format that is used,
and adds a new test to verify that characters are emitted as something
that GDB can print in a char-like way.

Fixes rust-lang#94458

…tolnay

Don't declare test_variadic_fnptr with two conflicting signatures

It is UB for LLVM and results in a compile error for Cranelift.

cc https://github.com/bjorn3/rustc_codegen_cranelift/issues/806
Fixes rust-lang#66690

…Dylan-DPC

Give more details in `Display` for `hir::Target`

Made because I was making a code change and got a very confusing "should be applied to a method, not a method" error.

```
error[E0718]: `into_try_type` language item must be applied to a method
   --> library\core\src\ops\try_trait.rs:352:32
    |
352 |     #[cfg_attr(not(bootstrap), lang = "into_try_type")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^ attribute should be applied to a method, not a method
```

With this change the error is more actionable

```
error[E0718]: `into_try_type` language item must be applied to a required trait method
   --> library\core\src\ops\try_trait.rs:352:32
    |
352 |     #[cfg_attr(not(bootstrap), lang = "into_try_type")]
    |                                ^^^^^^^^^^^^^^^^^^^^^^ attribute should be applied to a required trait method, not a provided trait method
```

Provide more useful documentation of conversion methods

I thought that the documentation for these methods needed to be a bit more explanatory for new users. For advanced users, the comments are relatively unnecessary. I think it would be useful to explain precisely what the method does. As a new user, when you see the `into` method, where the type is inferred, if you are new you don't even know what you convert to, because it is implicit. I believe this can help new users understand.