Fix: Add Book.current_page for screen compatibility

Author: jsfehler

encyclopaedia/book/book_ren.py

@@ -147,6 +147,11 @@ def active(self) -> 'EncEntry':
         """Get the page that's currently being viewed."""
         return self.pages[self._unlocked_page_index]
 
+    @property
+    def current_page(self) -> 'EncEntry':
+        """Alias for active. Used by screens."""
+        return self.active
+
     @property
     def percentage_unlocked(self) -> float:
         """Get the percentage of the Book that's unlocked.