DOCS-14838 dataSize command specify units

Author: jason-price-mongodb

source/reference/command/dataSize.txt

@@ -15,8 +15,8 @@ Definition
 
 .. dbcommand:: dataSize
 
-   The :dbcommand:`dataSize` command returns the data size for a set
-   of data within a certain range:
+   The :dbcommand:`dataSize` command returns the size in bytes for
+   the specified data:
 
    .. code-block:: javascript
 
@@ -104,9 +104,9 @@ and the upper bound of the key to be examined being ``{field: 100}``.
 
    db.runCommand({ dataSize: "database.collection", keyPattern: { field: 1 }, min: { field: 10 }, max: { field: 100 } })
 
-This will return a document that contains the size of all matching
-documents. Replace ``database.collection`` value with database
-and collection from your deployment.
+This returns a document with the size in bytes for all matching
+documents. Replace ``database.collection`` with the database and
+collection from your deployment.
 
 The amount of time required to return :dbcommand:`dataSize` depends on the
 amount of data in the collection.