Auto merge of #102896 - matthiaskrgr:rollup-jg5xawz, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #101360 (Point out incompatible closure bounds)
 - #101789 (`let`'s not needed in struct field definitions)
 - #102846 (update to syn-1.0.102)
 - #102871 (rustdoc: clean up overly complex `.trait-impl` CSS selectors)
 - #102876 (suggest candidates for unresolved import)
 - #102888 (Improve rustdoc-gui search-color test)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_parse/src/parser/item.rs

@@ -1788,7 +1788,23 @@ impl<'a> Parser<'a> {
                     }
                 }
             } else {
-                self.expected_ident_found()
+                let mut err = self.expected_ident_found();
+                if let Some((ident, _)) = self.token.ident() && ident.as_str() == "let" {
+                    self.bump(); // `let`
+                    let span = self.prev_token.span.until(self.token.span);
+                    err.span_suggestion(
+                        span,
+                        "remove the let, the `let` keyword is not allowed in struct field definitions",
+                        String::new(),
+                        Applicability::MachineApplicable,
+                    );
+                    err.note("the `let` keyword is not allowed in `struct` fields");
+                    err.note("see <https://doc.rust-lang.org/book/ch05-01-defining-structs.html> for more information");
+                    err.emit();
+                    self.bump();
+                    return Ok(ident);
+                }
+                err
             };
             return Err(err);
         }