Remove `token::{Open,Close}Delim`.

By replacing them with `{Open,Close}{Param,Brace,Bracket,Invisible}`.

PR #137902 made `ast::TokenKind` more like `lexer::TokenKind` by
replacing the compound `BinOp{,Eq}(BinOpToken)` variants with fieldless
variants `Plus`, `Minus`, `Star`, etc. This commit does a similar thing
with delimiters. It also makes `ast::TokenKind` more similar to
`parser::TokenType`.

This requires a few new methods:
- `TokenKind::is_{,open_,close_}delim()` replace various kinds of
  pattern matches.
- `Delimiter::as_{open,close}_token_kind` are used to convert
  `Delimiter` values to `TokenKind`.

Despite these additions, it's a net reduction in lines of code. This is
because e.g. `token::OpenParen` is so much shorter than
`token::OpenDelim(Delimiter::Parenthesis)` that many multi-line forms
reduce to single line forms. And many places where the number of lines
doesn't change are still easier to read, just because the names are
shorter, e.g.:
```
-   } else if self.token != token::CloseDelim(Delimiter::Brace) {
+   } else if self.token != token::CloseBrace {
```

1 files changed, 1 insertions, 4 deletions

diff --git a/compiler/rustc_ast/src/attr/mod.rs b/compiler/rustc_ast/src/attr/mod.rs
index d656d9b0b8a..3f0b9ea4138 100644
--- a/compiler/rustc_ast/src/attr/mod.rs
+++ b/compiler/rustc_ast/src/attr/mod.rs
@@ -416,10 +416,7 @@ impl MetaItem {
                 // This path is currently unreachable in the test suite.
                 unreachable!()
             }
-            Some(TokenTree::Token(
-                Token { kind: token::OpenDelim(_) | token::CloseDelim(_), .. },
-                _,
-            )) => {
+            Some(TokenTree::Token(Token { kind, .. }, _)) if kind.is_delim() => {
                 panic!("Should be `AttrTokenTree::Delimited`, not delim tokens: {:?}", tt);
             }
             _ => return None,