Move zoom height functionality to separate function.

Tools/idle/ZoomHeight.py

@@ -23,6 +23,9 @@ class ZoomHeight:
 
     def zoom_height_event(self, event):
         top = self.editwin.top
+        zoom_height(top)
+
+def zoom_height(top):
     geom = top.wm_geometry()
     m = re.match(r"(\d+)x(\d+)\+(-?\d+)\+(-?\d+)", geom)
     if not m: