Auto merge of #61541 - petrochenkov:tsp, r=oli-obk

syntax: Keep token span as a part of `Token`

In the world with proc macros and edition hygiene `Token` without a span is not self-contained.
In practice this means that tokens and spans are always stored and passed somewhere along with each other.
This PR combines them into a single struct by doing the next renaming/replacement:

- `Token` -> `TokenKind`
- `TokenAndSpan` -> `Token`
- `(Token, Span)` -> `Token`

Some later commits (https://github.com/rust-lang/rust/commit/fb6e2fe8fd6caed247857758c6c3549fe2b59527 and https://github.com/rust-lang/rust/commit/1cdee86940db892cd17239c26add5364335e895a) remove duplicate spans in `token::Ident` and `token::Lifetime`.
Those spans were supposed to be identical to token spans, but could easily go out of sync, as was noticed in https://github.com/rust-lang/rust/pull/60965#discussion_r285398523.
The `(Token, Span)` -> `Token` change is a soft pre-requisite for this de-duplication since it allows to avoid some larger churn (passing spans to most of functions classifying identifiers).

1 files changed, 1 insertions, 1 deletions

diff --git a/src/libsyntax/visit.rs b/src/libsyntax/visit.rs
index 334709b1521..4e6a8274a47 100644
--- a/src/libsyntax/visit.rs
+++ b/src/libsyntax/visit.rs
@@ -855,7 +855,7 @@ pub fn walk_attribute<'a, V: Visitor<'a>>(visitor: &mut V, attr: &'a Attribute)
 
 pub fn walk_tt<'a, V: Visitor<'a>>(visitor: &mut V, tt: TokenTree) {
     match tt {
-        TokenTree::Token(_, tok) => visitor.visit_token(tok),
+        TokenTree::Token(token) => visitor.visit_token(token),
         TokenTree::Delimited(_, _, tts) => visitor.visit_tts(tts),
     }
 }