v.surf.rst: clarify default smooth value

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@73554 15284696-431f-4ddb-bdfa-cd5b030d7da7

vector/v.surf.rst/main.c

@@ -281,7 +281,8 @@ int main(int argc, char *argv[])
     parm.rsm->key = "smooth";
     parm.rsm->type = TYPE_DOUBLE;
     parm.rsm->required = NO;
-    parm.rsm->description = _("Smoothing parameter");
+    parm.rsm->label = _("Smoothing parameter");
+    parm.rsm->description = _("Smoothing is by default 0.5 unless smooth_column is specified");
     parm.rsm->guisection = _("Parameters");
 
     parm.scol = G_define_option();