Fix some CI failures:

* Remove unnecesary parentheses in `Option<(&Foo)>`

Author: jugglerchris

src/map.rs

@@ -1967,7 +1967,7 @@ impl<'a, K, V> Iterator for Keys<'a, K, V> {
     type Item = &'a K;
 
     #[cfg_attr(feature = "inline-more", inline)]
-    fn next(&mut self) -> Option<(&'a K)> {
+    fn next(&mut self) -> Option<&'a K> {
         self.inner.next().map(|(k, _)| k)
     }
     #[cfg_attr(feature = "inline-more", inline)]
@@ -1987,7 +1987,7 @@ impl<'a, K, V> Iterator for Values<'a, K, V> {
     type Item = &'a V;
 
     #[cfg_attr(feature = "inline-more", inline)]
-    fn next(&mut self) -> Option<(&'a V)> {
+    fn next(&mut self) -> Option<&'a V> {
         self.inner.next().map(|(_, v)| v)
     }
     #[cfg_attr(feature = "inline-more", inline)]
@@ -2007,7 +2007,7 @@ impl<'a, K, V> Iterator for ValuesMut<'a, K, V> {
     type Item = &'a mut V;
 
     #[cfg_attr(feature = "inline-more", inline)]
-    fn next(&mut self) -> Option<(&'a mut V)> {
+    fn next(&mut self) -> Option<&'a mut V> {
         self.inner.next().map(|(_, v)| v)
     }
     #[cfg_attr(feature = "inline-more", inline)]