Linux desktop spec: remove "game engine" keyword

It seems this was overlooked when the game-engine was removed.

release/freedesktop/blender.desktop

@@ -78,7 +78,7 @@ Comment[wa]=Modelaedje 3D, animåcion, rindou eyet après-produccion
 Comment[zh_HK]=3D 模型、動畫、算圖和後製
 Comment[zh_CN]=3D 建模、动画、渲染和后期制作
 Comment[zh_TW]=3D 模型、動畫、算圖和後製
-Keywords=3d;cg;modeling;animation;painting;sculpting;texturing;video editing;video tracking;rendering;render engine;cycles;game engine;python;
+Keywords=3d;cg;modeling;animation;painting;sculpting;texturing;video editing;video tracking;rendering;render engine;cycles;python;
 Exec=blender %f
 Icon=blender
 Terminal=false