Rename some things related to literals.

- Rename `ast::Lit::token` as `ast::Lit::token_lit`, because its type is
  `token::Lit`, which is not a token. (This has been confusing me for a
  long time.)
  reasonable because we have an `ast::token::Lit` inside an `ast::Lit`.
- Rename `LitKind::{from,to}_lit_token` as
  `LitKind::{from,to}_token_lit`, to match the above change and
  `token::Lit`.

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -372,7 +372,7 @@ pub trait PrintState<'a>: std::ops::Deref<Target = pp::Printer> + std::ops::Dere
 
     fn print_literal(&mut self, lit: &ast::Lit) {
         self.maybe_print_comment(lit.span.lo());
-        self.word(lit.token.to_string())
+        self.word(lit.token_lit.to_string())
     }
 
     fn print_string(&mut self, st: &str, style: ast::StrStyle) {