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/element.rs

@@ -1305,10 +1305,7 @@ impl Element {
         match xmlSerialize::serialize(
             &mut writer,
             &self.upcast::<Node>(),
-            XmlSerializeOpts {
-                traversal_scope,
-                ..Default::default()
-            },
+            XmlSerializeOpts { traversal_scope },
         ) {
             Ok(()) => Ok(DOMString::from(String::from_utf8(writer).unwrap())),
             Err(_) => panic!("Cannot serialize element"),
@@ -3065,10 +3062,10 @@ impl VirtualMethods for Element {
     }
 
     fn parse_plain_attribute(&self, name: &LocalName, value: DOMString) -> AttrValue {
-        match name {
-            &local_name!("id") => AttrValue::from_atomic(value.into()),
-            &local_name!("name") => AttrValue::from_atomic(value.into()),
-            &local_name!("class") => AttrValue::from_serialized_tokenlist(value.into()),
+        match *name {
+            local_name!("id") => AttrValue::from_atomic(value.into()),
+            local_name!("name") => AttrValue::from_atomic(value.into()),
+            local_name!("class") => AttrValue::from_serialized_tokenlist(value.into()),
             _ => self
                 .super_type()
                 .unwrap()
@@ -3198,7 +3195,7 @@ impl VirtualMethods for Element {
     }
 }
 
-impl<'a> SelectorsElement for DomRoot<Element> {
+impl SelectorsElement for DomRoot<Element> {
     type Impl = SelectorImpl;
 
     #[allow(unsafe_code)]