Reduce usage of as_ref and as_mut.

src/func/callable_function.rs

@@ -178,7 +178,7 @@ impl CallableFunction {
     #[must_use]
     pub fn get_iter_fn(&self) -> Option<&IteratorFn> {
         match self {
-            Self::Iterator(f) => Some(f.as_ref()),
+            Self::Iterator(f) => Some(&**f),
             Self::Pure(..) | Self::Method(..) | Self::Plugin(..) => None,
 
             #[cfg(not(feature = "no_function"))]

src/func/native.rs

@@ -110,7 +110,7 @@ impl<'a, M: AsRef<[&'a Module]> + ?Sized, S: AsRef<str> + 'a + ?Sized>
         Self {
             engine: value.0,
             fn_name: value.1.as_ref(),
-            source: value.2.map(S::as_ref),
+            source: value.2.map(<_>::as_ref),
             global: Some(value.3),
             lib: value.4.as_ref(),
             pos: value.5,

src/func/script.rs

@@ -131,7 +131,7 @@ impl Engine {
                     lib
                 } else {
                     caches.push_fn_resolution_cache();
-                    lib_merged.push(fn_lib.as_ref());
+                    lib_merged.push(&**fn_lib);
                     lib_merged.extend(lib.iter().cloned());
                     &lib_merged
                 },