Doc: Use a navigation separator in the simple offline template

As we cannot style the navigation elements freely with the restricted
version of CSS that QTextBrowser supports, we need to inject
separator elements between the prev/next page links.

This change adds a 'bullet' character wrapped in a <span> as a
separator. A rule is added to the standard offline CSS to hide the
separator as it's not needed there.

Change-Id: I13220a2a60e2d3063f94bc7dff0e4320d0bed4f6
Reviewed-by: Martin Smith <martin.smith@digia.com>

doc/global/qt-html-templates-offline-simple.qdocconf

@@ -25,6 +25,9 @@ HTML.postpostheader = \
     "<div class=\"line\">\n" \
     "<div class=\"content mainContent\">\n"
 
+HTML.navigationseparator = \
+    "<span class=\"naviSeparator\">  &#9702;  </span>\n"
+
 # Add some padding around code snippets, as we cannot
 # currectly style them for QTextBrowser using only CSS.
 codeindent         = 2

doc/global/template/style/offline-simple.css

@@ -136,12 +136,12 @@ code {
 
 p.naviNextPrevious {
   text-align: right;
-  margin-right: 40px;
+  margin-right: 20px;
 }
 
-q.prevPage, a.nextPage {
-  margin-left: 30px;
- }
+span.naviSeparator {
+  white-space: pre;
+}
 
 .toc h3 {
   margin: 0px 0px 10px 6px;

doc/global/template/style/offline.css

@@ -192,6 +192,7 @@ Top navigation
      margin-left: 30px;
  }
 
+.naviSeparator { display: none }
 /*
 -----------
 footer and license