fixed a few spelling errors, mostly in comments and debug messages

src/qtgui/preview_w.cpp

@@ -750,7 +750,7 @@ bool Preview::loadDocInCurrentTab(const Rcl::Doc &idoc, int docnum)
             }
         }
     } else {
-        LOGDEB("Preview: no hilighting, loading " << lthr.fdoc.text.size() <<
+        LOGDEB("Preview: no highlighting, loading " << lthr.fdoc.text.size() <<
                " bytes\n");
         // No plaintorich() call.  In this case, either the text is
         // html and the html quoting is hopefully correct, or it's

src/qtgui/xmltosd.h

@@ -26,7 +26,7 @@
  *
  * <SD>                         <!-- Search Data -->
  *  <CL>                        <!-- Clause List -->
- *    <CLT>AND|OR</CLT>         <!-- conjunction AND is default, omitted -->
+ *    <CLT>AND|OR</CLT>         <!-- conjunction AND is default, ommitted -->
  *    <C>                       <!-- Clause -->
  *     [<NEG/>]                 <!-- Possible negation -->
  *     <CT>AND|OR|FN|PH|NE</CT> <!-- Clause type -->