Fixed some grammar from regions.html

article/regions.html

@@ -371,7 +371,7 @@ <h3>Some Useful Regions...</h3>
         <p>
             It's a checkerboard. Each pixel in here has two walls. Each "on" pixel is two walls, and each row
             is its own band, so assuming that we use 32-bit numbers for the positions, 8 bytes per pixel, and
-            8 extra bytes per band to store the top and bottom. Since is checkerboard is 16x10, that means we
+            8 extra bytes per band to store the top and bottom. Since this checkerboard is 16x10, that means we
             have (16*4+8) bytes = 72 bytes per band, and we have ten of them, for 720 bytes. In a bitmap,
             each row could be packed into two bytes, for a total of 20 bytes. Yeesh.
         </p>
@@ -381,7 +381,7 @@ <h3>Some Useful Regions...</h3>
             the weight of such regions and tricks, but it was an important part of history that let us figure out
             how to move forward. As the
             <a href="http://cgit.freedesktop.org/xorg/proto/compositeproto/plain/compositeproto.txt">COMPOSITE extension specification</a>
-            puts it, "clever hacks are an awfully close substitute for changes in the underlying system".
+            puts it: "clever hacks are an awfully close substitute for changes in the underlying system".
         </p>
         <p>
             Window shapes, both on the output and input sides, are clearly the most useful case for complex