v.net: manual cosmetics (fix sections) (merge https://trac.osgeo.org/grass/changeset/59682 from trunk)

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@59683 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.net/v.net.html

@@ -108,7 +108,7 @@ connectivity. These include:
 <em><a href="v.net.timetable.html">v.net.timetable</a></em>, and 
 <em><a href="v.net.visibility.html">v.net.visibility</a></em>.
     
-<h3>NOTES</h3>
+<h2>NOTES</h2>
 
 For a vector map prepared for network analysis in GRASS, nodes are 
 represented by the grass-internal geometry type <em>node</em> and arcs 
@@ -120,7 +120,7 @@ or <em><a href="v.edit.html">v.edit</a></em> can be used.  See also
 the <a href="lrs.html">Linear Referencing System</a> available in
 GRASS GIS.
 
-<h3>EXAMPLES</h3>
+<h2>EXAMPLES</h2>
 
 The examples are <a href="http://www.grassbook.org/data_menu3rd.php">North Carolina dataset</a> based.