Remove pronoun I from voice for lack of lone addressor

There is no single author listed, the credits are to the
GitHub team, so match up narration to fit that angle.

Pulls it back from single author perspective driving it that
may have existed long ago.

index.html

@@ -5,7 +5,7 @@ layout: reference
   <h2>Introduction to the Git Reference</h2>
   <div class="block">
     <p>
-    This is the Git reference site. This is meant to be a quick
+    This is the Git reference site. It is meant to be a quick
     reference for learning and remembering the most important and
     commonly used Git commands.  The commands are organized into
     sections of the type of operation you may be trying to do, and
@@ -28,7 +28,7 @@ layout: reference
   <h2>How to Think Like Git</h2>
   <div class="block">
     <p>
-    The first thing that is important to understand about Git is
+    The first important thing to understand about Git is
     that it thinks about version control very differently than
     Subversion or Perforce or whatever SCM you may be used to. It
     is often easier to learn Git by trying to forget your assumptions