More doc tidying

* Update regrass.rst
* Update cleaners.rst

docs/plugins/cleaners.rst

@@ -105,8 +105,8 @@ Options
     cleans contaminants *off* of items.
 ``-g``, ``--grass``
     Remove unused (entirely depleted) grass events from map blocks. DF will
-    create a grass events for each type of grass that grows in a block, but
-    doesn't remove them if you pave over everything, or the grass got
+    create a grass event for each type of grass that grows in a block, but
+    doesn't remove them if you pave over the block or if the grass got
     depleted and entirely replaced with a different type. Could possibly
     improve FPS if you had a ton of unused grass events everywhere (a likely
     outcome of using ``regrass --new``). Requires ``--map`` option to be

docs/plugins/regrass.rst

@@ -78,7 +78,10 @@ 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.
+    begin with. Will still fail in incompatible biomes. This can add an excessive
+    amount of grass events to your map, so it may be desirable to run
+    ``clean --map --grass --only`` (see: `cleaners`) to clean up any unused events
+    afterwards.
 ``-f``, ``--force``
     Force a grass type on tiles with no compatible grass types. Unsets the
     ``no_grow`` flag on all tiles. The ``--new`` option takes precedence for