r.stats.zonal manual: added link to r.stats.quantile

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@72645 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.stats.zonal/r.stats.zonal.html

@@ -10,7 +10,7 @@ in a "base layer". A variety of standard statistical measures are possible
 <em>r.stats.zonal</em> is intended to be a partial replacement for
 <em><a href="r.statistics.html">r.statistics</a></em>, with support
 for floating-point cover maps at the expense of not supporting
-quantiles. For this, see <em>r.stats.quantile</em>.
+quantiles. For this, see <em><a href="r.stats.quantile.html">r.stats.quantile</a></em>.
 
 <h2>EXAMPLE</h2>