switch from one space indent to two space indent before public: and private:

This matches what astyle does, so it's one less thing to stress about

doc/CODING_STYLE.html

@@ -5782,7 +5782,7 @@ beginning of the line.</p>
 
 <div class="summary">
 <p>Sections in <code>public</code>, <code>protected</code> and
-<code>private</code> order, each indented one space.</p>
+<code>private</code> order, each indented two spaces.</p>
 </div>
 
 <div class="stylebody">
@@ -5821,7 +5821,7 @@ needed) is:</p>
 
   <li>The <code>public:</code>, <code>protected:</code>,
   and <code>private:</code> keywords should be indented
-  one space.</li>
+  two spaces.</li>
 
   <li>Except for the first instance, these keywords
   should be preceded by a blank line. This rule is