fix typo

raster/r.sim/r.sim.water/r.sim.water.html

@@ -115,7 +115,7 @@ <h2>DESCRIPTION</h2>
 The model tries to keep water "shallow" with maximum shallow water
 depth defined by <b>hmax</b> default 0.3 meters. However, water depths
 much higher than <b>hmax</b> can be observed if water accumulates in
-natural sinks or river beds.Depending on the area of interest and the
+natural sinks or river beds. Depending on the area of interest and the
 used digital elevation model, <b>hmax</b>, <b>halpha</b> and
 <b>hbeta</b> might need to be adjusted in order to deal realistically
 with elevation depressions or obstacles.