Auto merge of #123468 - compiler-errors:precise-capturing, r=oli-obk

Implement syntax for `impl Trait` to specify its captures explicitly (`feature(precise_capturing)`)

Implements `impl use<'a, 'b, T, U> Sized` syntax that allows users to explicitly list the captured parameters for an opaque, rather than inferring it from the opaque's bounds (or capturing *all* lifetimes under 2024-edition capture rules). This allows us to exclude some implicit captures, so this syntax may be used as a migration strategy for changes due to #117587.

We represent this list of captured params as `PreciseCapturingArg` in AST and HIR, resolving them between `rustc_resolve` and `resolve_bound_vars`. Later on, we validate that the opaques only capture the parameters in this list.

We artificially limit the feature to *require* mentioning all type and const parameters, since we don't currently have support for non-lifetime bivariant generics. This can be relaxed in the future.

We also may need to limit this to require naming *all* lifetime parameters for RPITIT, since GATs have no variance. I have to investigate this. This can also be relaxed in the future.

r? `@oli-obk`

Tracking issue:

- https://github.com/rust-lang/rust/issues/123432

compiler/rustc_hir_pretty/src/lib.rs

@@ -95,6 +95,7 @@ impl<'a> State<'a> {
             Node::PatField(a) => self.print_patfield(a),
             Node::Arm(a) => self.print_arm(a),
             Node::Infer(_) => self.word("_"),
+            Node::PreciseCapturingNonLifetimeArg(param) => self.print_ident(param.ident),
             Node::Block(a) => {
                 // Containing cbox, will be closed by print-block at `}`.
                 self.cbox(INDENT_UNIT);