explain coefbh and coefdh options a bit more clearly

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@50282 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.sun/main.c

@@ -346,7 +346,7 @@ int main(int argc, char *argv[])
     parm.coefbh->required = NO;
     parm.coefbh->gisprompt = "old,cell,raster";
     parm.coefbh->description =
-	_("Name of real-sky beam radiation coefficient input raster map [-]");
+	_("Name of real-sky beam radiation coefficient (thick cloud) input raster map [0-1]");
     parm.coefbh->guisection = _("Input_options");
 
     parm.coefdh = G_define_option();
@@ -355,7 +355,7 @@ int main(int argc, char *argv[])
     parm.coefdh->required = NO;
     parm.coefdh->gisprompt = "old,cell,raster";
     parm.coefdh->description =
-	_("Name of real-sky diffuse radiation coefficient input raster map [-]");
+	_("Name of real-sky diffuse radiation coefficient (haze) input raster map [0-1]");
     parm.coefdh->guisection = _("Input_options");
 
     parm.horizon = G_define_option();