repo-feature-usage: improve chart description (#114)

docs/repos-feature-usage.html

@@ -12,10 +12,14 @@ <h3>Repository Feature Usage</h3>
 		></canvas>
 	<div class="info-box">
 		<p>
-			The percentage of active repositories located in organizations, using at least one <a href="https://help.github.com/articles/about-protected-branches/">protected branch</a>, and having at least one <a href="https://help.github.com/articles/about-topics/">topic</a> assigned to it.
+			The percentage of active repositories located in organizations with at least one active <a href="https://help.github.com/articles/about-protected-branches/">protected branch</a> and at least one <a href="https://help.github.com/articles/about-topics/">topic</a> assigned to them.
 		</p>
 		<p>
 			In this context, <em>active</em> designates repositories with at least one pushed commit in the last four weeks.
 		</p>
+		<p>
+			All shared branches (for example, master and release branches) should be protected to ensure that they cannot be deleted or rewritten by accident.
+			Furthermore, tagging repository with associated topics increases their discoverability.
+		</p>
 	</div>
 </div>