Fix clippy::derivable_impls lint

bindgen/codegen/mod.rs

@@ -4107,9 +4107,10 @@ impl FromStr for AliasVariation {
 }
 
 /// Enum for how non-`Copy` `union`s should be translated.
-#[derive(Copy, Clone, PartialEq, Eq, Debug)]
+#[derive(Copy, Clone, PartialEq, Eq, Debug, Default)]
 pub enum NonCopyUnionStyle {
     /// Wrap members in a type generated by `bindgen`.
+    #[default]
     BindgenWrapper,
     /// Wrap members in [`::core::mem::ManuallyDrop`].
     ///
@@ -4129,12 +4130,6 @@ impl fmt::Display for NonCopyUnionStyle {
     }
 }
 
-impl Default for NonCopyUnionStyle {
-    fn default() -> Self {
-        Self::BindgenWrapper
-    }
-}
-
 impl FromStr for NonCopyUnionStyle {
     type Err = std::io::Error;
 

bindgen/lib.rs

@@ -167,24 +167,19 @@ impl Default for CodegenConfig {
 }
 
 /// Formatting tools that can be used to format the bindings
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
 #[non_exhaustive]
 pub enum Formatter {
     /// Do not format the bindings.
     None,
     /// Use `rustfmt` to format the bindings.
+    #[default]
     Rustfmt,
     #[cfg(feature = "prettyplease")]
     /// Use `prettyplease` to format the bindings.
     Prettyplease,
 }
 
-impl Default for Formatter {
-    fn default() -> Self {
-        Self::Rustfmt
-    }
-}
-
 impl FromStr for Formatter {
     type Err = String;