contribute/development page: update links in the side panel (#324)

* contribute/development page: update links in the side panel

* Update themes/grass/layouts/contribute/devel.html

Co-authored-by: Vaclav Petras <wenzeslaus@gmail.com>

Co-authored-by: Vaclav Petras <wenzeslaus@gmail.com>

themes/grass/layouts/contribute/devel.html

@@ -40,10 +40,10 @@ <h3>Quick links</h3>
 
             </nav>
             <ul class="list-unstyled">
-	            <li><i class="ms ms-grass-gis"></i> &#160;<a href="https://trac.osgeo.org/grass/wiki/HowToContribute" target="_blank">How to contribute</a></li>
+	            <li><i class="ms ms-grass-gis"></i> &#160;<a href="https://github.com/OSGeo/grass/blob/master/CONTRIBUTING.md" target="_blank">How to contribute</a></li>
                 <li><i class="fa fa-gears"></i> &#160;<a href="https://grasswiki.osgeo.org/wiki/GRASS_GIS_APIs" target="_blank">API's wiki page</a></li>
-                <li><i class="fa fa-file-text"></i> &#160;<a href="https://grass.osgeo.org/programming7/" target="_blank">Developer manual</a></li>
-                <li><i class="fa fa-code"></i> &#160;<a href="https://github.com/OSGeo/grass/blob/master/CONTRIBUTING.md" target="_blank">How to use git to contribute</a></li>
+                <li><i class="fa fa-file-text"></i> &#160;<a href="https://grass.osgeo.org/programming8/" target="_blank">Developer manual</a></li>
+                <li><i class="fa fa-code"></i> &#160;<a href="https://trac.osgeo.org/grass/wiki/Submitting" target="_blank">Submitting guidelines</a></li>
                 <li><i class="fa fa-code-fork"></i> &#160;<a href="https://trac.osgeo.org/grass/wiki/HowToGit" target="_blank">How to use git</a></li>
 	            <li><i class="fa fa-github"></i> &#160;<a href="https://github.com/OSGeo/grass/" target="_blank">Source code</a></li>
 	            <li><i class="fa fa-bug"></i> &#160;<a href="https://github.com/OSGeo/grass/issues" target="_blank">Bug Tracker</a></li>