maint: whitespace cleanup

* .dir-locals.el (html-mode): Let emacs help out.
* cfg.mk (sc_TAB_in_indentation): Check more files.
* docs/internals/command.html.in: Fix offenders.
* docs/formatdomain.html.in: Likewise.
* docs/internals.html.in: Likewise.
Reported by Jiri Denemark.

docs/internals.html.in

@@ -10,10 +10,10 @@
 
     <ul>
       <li>Introduction to basic rules and guidelines for <a href="hacking.html">hacking<a>
-	    on libvirt code</li>
+            on libvirt code</li>
       <li>Guide to adding <a href="api_extension.html">public APIs<a></li>
       <li>Approach for <a href="internals/command.html">spawning commands</a> from
-	libvirt driver code</li>
+        libvirt driver code</li>
     </ul>
 
   </body>