Rename and clear bad code

src/word.rs

@@ -18,7 +18,7 @@ pub struct WordState {
 }
 
 impl NavigatedPage<WordMessage> for WordState {
-    fn navigate(&self, message: &WordMessage) -> Option<Page> {
+    fn navigate(&mut self, message: &WordMessage) -> Option<Page> {
         if let Back = message {
             Some(PreviousPage)
         } else {