DOCS-15728 sh.moveChunk can't be used with hashed shard key (mongodb#2386)

* DOCS-15728 sh.moveChunk can't be used with hashed shard key

* add monospacing

Author: lindseymoore

source/reference/method/sh.moveChunk.txt

@@ -1,3 +1,5 @@
+.. _sh-move-chunk:
+
 ==============
 sh.moveChunk()
 ==============
@@ -25,6 +27,13 @@ Definition
       automatically migrate :term:`chunks <chunk>`, and avoid calling
       :method:`sh.moveChunk()` directly.
 
+   .. warning:: 
+      
+      This command cannot be used for hashed shard keys, as it 
+      uses the ``find`` option from the :dbcommand:`moveChunk` command. 
+      To move a chunk with a :term:`hashed shard key`, use the 
+      :dbcommand:`moveChunk` command specifying the ``bounds`` field. 
+
    :method:`sh.moveChunk()` takes the following arguments:
 
    .. list-table::