Capitalize GitHub

spec.txt

@@ -248,7 +248,7 @@ satisfactory replacement for a spec.
 
 Because there is no unambiguous spec, implementations have diverged
 considerably.  As a result, users are often surprised to find that
-a document that renders one way on one system (say, a github wiki)
+a document that renders one way on one system (say, a GitHub wiki)
 renders differently on another (say, converting to docbook using
 pandoc).  To make matters worse, because nothing in Markdown counts
 as a "syntax error," the divergence often isn't discovered right away.