Rollup merge of #99435 - CAD97:revert-dollar-dollar-crate, r=Mark-Simulacrum

Revert "Stabilize $$ in Rust 1.63.0"

This mechanically reverts commit 9edaa76adc, the one commit from #95860.

https://github.com/rust-lang/rust/issues/99035; the behavior of `$$crate` is potentially unexpected and not ready to be stabilized. https://github.com/rust-lang/rust/pull/99193 attempts to forbid `$$crate` without also destabilizing `$$` more generally.

`@rustbot` modify labels +T-compiler +T-lang +P-medium +beta-nominated +relnotes

(applying the labels I think are accurate from the issue and alternative partial revert)

cc `@Mark-Simulacrum`

compiler/rustc_expand/src/mbe/quoted.rs

@@ -234,6 +234,8 @@ fn parse_tree(
                             sess,
                             &Token { kind: token::Dollar, span },
                         );
+                    } else {
+                        maybe_emit_macro_metavar_expr_feature(features, sess, span);
                     }
                     TokenTree::token(token::Dollar, span)
                 }