Update regrass.rst

Author: Bumber64

docs/plugins/regrass.rst

@@ -78,8 +78,8 @@ Options
 ``-n``, ``--new``
     Adds all biome-compatible grass types that were not originally present in
     the map block. Allows regrass to work in blocks that never had any grass to
-    begin with. Will still fail in incompatible biomes. This can add an excessive
-    number of grass events to your map, so it may be desirable to run
+    begin with. Will still fail in incompatible biomes. Note: This can add an
+    excessive number of grass events to your map, so it may be desirable to run
     ``clean --map --grass --only`` (see: `cleaners`) afterwards to clean up any
     unused events.
 ``-f``, ``--force``