v.neighbors manual: example expanded (closes trac https://trac.osgeo.org/grass/ticket/2488)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@62773 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.neighbors/v.neighbors.html

@@ -18,6 +18,10 @@ d.rast schools_wake_3000m
 d.vect schools_wake
 </pre></div>
 
+The result gives for each grid cell the number of points (here: schools)
+not farther than 1500 meter away (half of the given <em>size</em> value)
+from the respective cell center.
+
 <h2>SEE ALSO</h2>
 
 <em>