r.stats manual: explanation on -x flag added (contributed by nikosa, Nikos Alexandris)

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@74433 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.stats/r.stats.html

@@ -15,10 +15,11 @@ will be stated also in number of cells.
 
 <h2>NOTES</h2>
 
-If a single raster map is specified, a list of categories will be
-printed. If multiple raster maps are specified, a cross-tabulation
-table for each combination of categories in the raster maps will be
-printed.
+If a single raster map is specified, a list of categories will be printed.
+The <b>-x</b> flag will print x and y (column and row) starting with 1
+(both first row and first column are indexed with 1). If multiple raster maps
+are specified, a cross-tabulation table for each combination of categories in
+the raster maps will be printed.
 
 <p>
 For example, if one raster map was specified, the output would look like: