Add a tip about using git grep when removing a port.

Sponsored by:	Absolight

en_US.ISO8859-1/articles/committers-guide/article.xml

@@ -4111,6 +4111,13 @@ Relnotes:           yes</programlisting>
 		    <para>No other ports should contain any reference
 		      to the port's directory or PKGNAME in their
 		      Makefiles</para>
+
+		    <tip>
+		      <para>When using <application>Git</application>,
+			consider using <command>git grep</command>, it
+			is much faster than <command>grep
+			  -r</command>.</para>
+		    </tip>
 		  </listitem>
 		</itemizedlist>
 	      </listitem>