Remove references to maybe_whole_expr.

It was removed in rust-lang#126571.

Author: nnethercote

compiler/rustc_ast/src/token.rs

@@ -699,8 +699,7 @@ impl Token {
         false
     }
 
-    /// Would `maybe_whole_expr` in `parser.rs` return `Ok(..)`?
-    /// That is, is this a pre-parsed expression dropped into the token stream
+    /// Is this a pre-parsed expression dropped into the token stream
     /// (which happens while parsing the result of macro expansion)?
     pub fn is_whole_expr(&self) -> bool {
         if let Interpolated(nt) = &self.kind

compiler/rustc_parse/src/parser/mod.rs

@@ -101,7 +101,6 @@ pub enum TrailingToken {
     MaybeComma,
 }
 
-/// Like `maybe_whole_expr`, but for things other than expressions.
 #[macro_export]
 macro_rules! maybe_whole {
     ($p:expr, $constructor:ident, |$x:ident| $e:expr) => {