screenshot-window-sizer: Rearrange calculation

eslint has a rule to prohibit unnecessary parentheses. While this is
generally a good idea stylistically, the parentheses in a calculation
of (a / b) * c add more clarity, as a / b * c lacks the unambiguity of
proper math notation:

   a                a
  --- * c   vs   -------
   b              b * c

We can still follow the style rule by rearranging to the unambiguous
c * a / b.

https://gitlab.gnome.org/GNOME/gnome-shell-extensions/merge_requests/91

extensions/screenshot-window-sizer/extension.js

@@ -128,7 +128,7 @@ function cycleScreenshotSizes(display, window, binding) {
     // The new size might have been constrained by geometry hints (e.g. for
     // a terminal) - in that case, include the actual ratio to the message
     // we flash
-    let actualNumerator = (newOuterRect.width / newOuterRect.height) * 9;
+    let actualNumerator = 9 * newOuterRect.width / newOuterRect.height;
     if (Math.abs(actualNumerator - 16) > 0.01)
         message += ' (%.2f:9)'.format(actualNumerator);