Elide lifetimes where possible after rustup (#34824)

The new version of rust allows us to elide some lifetimes and clippy is
now complaining about this. This change elides them where possible and
removes the clippy exceptions.

Fixes #34804.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/dom/bindings/str.rs

@@ -356,7 +356,7 @@ impl From<String> for DOMString {
     }
 }
 
-impl<'a> From<&'a str> for DOMString {
+impl From<&str> for DOMString {
     fn from(contents: &str) -> DOMString {
         DOMString::from(String::from(contents))
     }