yoda: warning cleanup sweep (dead code + clippy --fix) (squashed)

Squash of 4 yoda commits:
- 84437e21 yoda: libcosmic-yoda dead-code purge (14->0 warnings)
- 999db0a4 yoda: cosmic-theme cleanup (4->0 warnings) — workspace at 0 warnings total
- 4743bb8e yoda: cargo clippy --fix on libcosmic-yoda (115->33 warnings)
- 675f3b59 chore: reduce local stack warnings

src/widget/spin_button.rs

@@ -23,7 +23,7 @@ pub fn spin_button<'a, T, M>(
 where
     T: Copy + Sub<Output = T> + Add<Output = T> + PartialOrd,
 {
-    let mut button = SpinButton::new(
+    let button = SpinButton::new(
         label,
         value,
         step,
@@ -34,9 +34,11 @@ where
     );
 
     #[cfg(feature = "a11y")]
-    {
+    let button = {
+        let mut button = button;
         button = button.name(name.into());
-    }
+        button
+    };
 
     button
 }
@@ -54,20 +56,22 @@ pub fn vertical<'a, T, M>(
 where
     T: Copy + Sub<Output = T> + Add<Output = T> + PartialOrd,
 {
-    let mut button = SpinButton::new(
+    let button = SpinButton::new(
         label,
         value,
         step,
         min,
         max,
-        Orientation::Horizontal,
+        Orientation::Vertical,
         on_press,
     );
 
     #[cfg(feature = "a11y")]
-    {
+    let button = {
+        let mut button = button;
         button = button.name(name.into());
-    }
+        button
+    };
 
     button
 }