Increase conversion rate of short grass to grass (took forever)

At the previous rate, it would take almost 27 days for half of the
short grass to convert to regular dirt with grass. And therefore
54 days in total to reach 75% conversion, 81 days for 87.5%, etc.

At the new rate, it should take about 4.5 hours for half of the
short grass to convert back to dirt wit grass.

dryplants/settings.txt

@@ -40,8 +40,8 @@ TALL_GRASS_RARITY					=	75		-- percent
 
 
 -- short grass becomes dirt with grass again
-GRASS_REGROWING_TIME 				= 	16800 	-- seconds
-GRASS_REGROWING_CHANCE 				= 	0.5		-- percent
+GRASS_REGROWING_TIME 				= 	1200 	-- seconds
+GRASS_REGROWING_CHANCE 				= 	5		-- percent
 
 HAY_DRYING_TIME 					= 	3600 	-- seconds