split view: Nix special apostrophe in comment in split_view_controller.h

While editing split_view_controller.h in emacs, I am always constantly
inconvenienced by error messages for reasons related to "it’s" in a
comment. The apostrophe is actually an unusual character. Compare:

' is on your keyboard.
’ is in the comment in split_view_controller.h.

There should not even be an apostrophe there, because the grammar of the
sentence requires the possessive "its" rather than the contraction.

Change-Id: I2b9e0397ad5019940769d224959a05bb073837a5
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1829651Reviewed-by: Xiaoqian Dai <xdai@chromium.org>
Commit-Queue: Avery Musbach <amusbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700858}

ash/wm/splitview/split_view_controller.h

@@ -413,7 +413,7 @@ class ASH_EXPORT SplitViewController : public aura::WindowObserver,
   // to left or right, the left and right window will be resized accordingly.
   std::unique_ptr<SplitViewDivider> split_view_divider_;
 
-  // A black scrim layer that fades in over a window when it’s width drops under
+  // A black scrim layer that fades in over a window when its width drops under
   // 1/3 of the width of the screen, increasing in opacity as the divider gets
   // closer to the edge of the screen.
   std::unique_ptr<ui::Layer> black_scrim_layer_;