KEYSIZE MAX = 1000 - en

See: 
MapServer/MapServer#7154

Author: gu-LGB

en/mapfile/legend.txt

@@ -52,7 +52,7 @@ INTERLACE [on|off]
 
 KEYSIZE [x][y]
     Size of symbol key boxes in pixels. Default is 20 by 10. Minimum
-    values are 5, and maximum values are 200. 
+    values are 5, and maximum values are 1000. 
 
 .. index::
    pair: LEGEND; KEYSPACING