[gnome-shell] workspace: Use operator shorthand

[Florian Müllner <fmuellner src gnome org>]

commit 1da993745336119e747bddd2ba448dd94f77dd94
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Aug 19 21:12:21 2019 +0200

    workspace: Use operator shorthand
    
    Shorthands like a += b are well-established, so prefer them over the
    less concise a = a + b.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/710

 js/ui/workspace.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index d16a5c1ca5..b38a9428e8 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -948,7 +948,7 @@ var LayoutStrategy = class {
             y += row.height * row.additionalScale + this._rowSpacing;
         }
 
-        compensation = compensation / 2;
+        compensation /= 2;
 
         for (let i = 0; i < rows.length; i++) {
             let row = rows[i];