docs: generate permalinks correctly for rst2html output

The rst2html output generates the links for headings in a slightly
different way than we do for docs written in HTML, so we must match
another scenario when generating back links.

rst2html will also use <h1> tags for both the document title and
the first level of section titles, so we must expand the matching
to allow for this too.
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

docs/libvirt.css

@@ -419,6 +419,7 @@ a.headerlink {
     visibility: hidden;
 }
 
+h1:hover > a.headerlink,
 h2:hover > a.headerlink,
 h3:hover > a.headerlink,
 h4:hover > a.headerlink,

docs/page.xsl

@@ -176,12 +176,15 @@
     <xsl:apply-templates select="exsl:node-set($inchtml)/html:html/html:body/*" mode="content"/>
   </xsl:template>
 
-  <xsl:template match="html:h2 | html:h3 | html:h4 | html:h5 | html:h6" mode="content">
+  <xsl:template match="html:h1 | html:h2 | html:h3 | html:h4 | html:h5 | html:h6" mode="content">
     <xsl:element name="{name()}">
       <xsl:apply-templates mode="copy" />
       <xsl:if test="./html:a/@id">
         <a class="headerlink" href="#{html:a/@id}" title="Permalink to this headline">&#xb6;</a>
       </xsl:if>
+      <xsl:if test="./html:a[@class='toc-backref']">
+        <a class="headerlink" href="#{../@id}" title="Permalink to this headline">&#xb6;</a>
+      </xsl:if>
     </xsl:element>
   </xsl:template>