fix plural typo (#220)

Author: SuggonM

wiki/graphics/2d/ninepatches.md

@@ -1,7 +1,7 @@
 ---
 title: Ninepatches
 ---
-This article introduce NinePatch images, how they can be created and how they
+This article introduces NinePatch images, how they can be created and how they
 are used in a libGDX context.
 
 ## Before you start
@@ -156,4 +156,4 @@ When this is the only picture from the _export_-folder run in the SkinPacker the
 }
 ```
 
-We see that the packer actually defined nine patches (somebody should be mind blown by now!). One huge advantage with this is that we are no longer constrained to the 1 square for each region (as opposed to instantiate Ninepatches manually). We can now define more fine-grained nine patches. In addition to this, its much easier to just alter an image and run it through the packer, and it will define regions.
+We see that the packer actually defined nine patches (somebody should be mind blown by now!). One huge advantage with this is that we are no longer constrained to the 1 square for each region (as opposed to instantiate Ninepatches manually). We can now define more fine-grained nine patches. In addition to this, its much easier to just alter an image and run it through the packer, and it will define regions.