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/htmlelement.rs

@@ -954,7 +954,7 @@ impl VirtualMethods for HTMLElement {
     }
 
     fn bind_to_tree(&self, context: &BindContext) {
-        if let Some(ref super_type) = self.super_type() {
+        if let Some(super_type) = self.super_type() {
             super_type.bind_to_tree(context);
         }
         let element = self.as_element();
@@ -975,7 +975,7 @@ impl VirtualMethods for HTMLElement {
     }
 
     fn unbind_from_tree(&self, context: &UnbindContext) {
-        if let Some(ref super_type) = self.super_type() {
+        if let Some(super_type) = self.super_type() {
             super_type.unbind_from_tree(context);
         }