Fix incorrect renderinterval description. In the code, renderinterval is the number of seconds the render thread sleeps between tile renders, not the number of tiles to be rendered in a second.

Configuration.txt.md

@@ -188,7 +188,7 @@ display-whitelist: false
 ***
 
 ### renderinterval 
-This defines how often dynmap attempts to render tiles. Each tile is an image of your map, the size can range from just a few blocks^2 to thousands^2 depending on quality profile and zoom level of the tile being rendered. The average map will have tens of thousands of tiles, this setting should not be set above 1. It is measured in tiles per second.   
+This defines how often dynmap renders tiles, measured in seconds, with higher values reducing the rate at which tiles are rendered. Each tile is an image of your map. This can be a decimal value. If not defined, the value is set to 0.5 seconds.   
 The default is: 
 ```
 renderinterval: 1