Implement Eq for NSValue

Note that `NSNumber` already implements `Eq` since 3661935, which was
the biggest blocker for adding this implementation.

framework-crates/objc2-foundation/src/value.rs

@@ -172,6 +172,8 @@ impl PartialEq for NSValue {
     }
 }
 
+impl Eq for NSValue {}
+
 impl fmt::Debug for NSValue {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         let enc = self.encoding().unwrap_or("(NULL)");

framework-crates/objc2-foundation/translation-config.toml

@@ -67,10 +67,9 @@ class.NSProcessInfo.derives = "PartialEq, Eq, Hash"
 class.NSString.derives = "PartialEq, Eq, Hash"
 class.NSUUID.derives = "PartialEq, Eq, Hash"
 
-# Overridden because whether or not it is Eq depends on the inner value
+# Overridden to use more performant implementation for `PartialEq`
 class.NSValue.derives = ""
 class.NSNumber.derives = ""
-class.NSDecimalNumber.derives = "Debug, PartialEq, Hash"
 
 # Returns `nil` on Apple and GNUStep throws an exception on all other messages
 # to this invalid instance.