Rollup merge of #95211 - terrarier2111:improve-parser, r=compiler-errors

Improve parser diagnostics

This pr fixes https://github.com/rust-lang/rust/issues/93867 and contains a couple of diagnostics related changes to the parser.
Here is a short list with some of the changes:
- don't suggest the same thing that is the current token
- suggest removing the current token if the following token is one of the suggestions (maybe incorrect)
- tell the user to put a type or lifetime after where if there is none (as a warning)
- reduce the amount of tokens suggested (via the new eat_noexpect and check_noexpect methods)

If any of these changes are undesirable, i can remove them, thanks!

compiler/rustc_parse/src/parser/stmt.rs

@@ -260,7 +260,10 @@ impl<'a> Parser<'a> {
                     if let Ok(snip) = self.span_to_snippet(pat.span) {
                         err.span_label(pat.span, format!("while parsing the type for `{}`", snip));
                     }
-                    let err = if self.check(&token::Eq) {
+                    // we use noexpect here because we don't actually expect Eq to be here
+                    // but we are still checking for it in order to be able to handle it if
+                    // it is there
+                    let err = if self.check_noexpect(&token::Eq) {
                         err.emit();
                         None
                     } else {