simplify undo/redo menu button visibility checks

Author: tibbi

app/src/main/kotlin/com/simplemobiletools/notes/pro/activities/MainActivity.kt

@@ -167,16 +167,13 @@ class MainActivity : SimpleActivity() {
         val isCurrentItemChecklist = isCurrentItemChecklist()
 
         main_toolbar.menu.apply {
-            val areButtonsVisible = (showRedoButton || showUndoButton) && mCurrentNote.type == NoteType.TYPE_TEXT.value
             findItem(R.id.undo).apply {
-                isVisible = areButtonsVisible
-                isEnabled = showUndoButton && mCurrentNote.type == NoteType.TYPE_TEXT.value
+                isVisible = showUndoButton && mCurrentNote.type == NoteType.TYPE_TEXT.value
                 icon?.alpha = if (isEnabled) 255 else 127
             }
 
             findItem(R.id.redo).apply {
-                isVisible = areButtonsVisible
-                isEnabled = showRedoButton && mCurrentNote.type == NoteType.TYPE_TEXT.value
+                isVisible = showRedoButton && mCurrentNote.type == NoteType.TYPE_TEXT.value
                 icon?.alpha = if (isEnabled) 255 else 127
             }