clippy: fix several lint warns (#32126)

As seems #31500 still remain opened here's the next partial fix.

Fixed list: `unused_mut`, `clippy::needless_borrow`,
`clippy::match_ref_pats`, `clippy::borrow_deref_ref`, `clippy::ptr_eq`,
`clippy::unnecessary_cast`, `clippy::derivable_impls`,
`clippy::collapsible_match`, `clippy::extra_unused_lifetimes`,
`clippy::map_clone`, `clippy::manual_filter`.


- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes are part of #31500.
- [x] These changes do not require tests because are only cosmetic.

components/script/dom/elementinternals.rs

@@ -143,7 +143,7 @@ impl ElementInternals {
         }
 
         if let SubmissionValue::FormData(datums) = &*self.submission_value.borrow() {
-            entry_list.extend(datums.iter().map(|d| d.clone()));
+            entry_list.extend(datums.iter().cloned());
             return;
         }
         let name = self
@@ -169,7 +169,7 @@ impl ElementInternals {
                 entry_list.push(FormDatum {
                     ty: DOMString::from("file"),
                     name,
-                    value: FormDatumValue::File(DomRoot::from_ref(&*file)),
+                    value: FormDatumValue::File(DomRoot::from_ref(file)),
                 });
             },
         }