fix typos

Author: shuangela

source/reference/method/MongoDBCollection-listSearchIndexes.txt

@@ -42,7 +42,7 @@ Parameters
        - integer
        - The maximum number of documents within each batch returned in a query result, which applies 
          to the ``aggregate`` command. By default, the ``aggregate`` command has an initial batch size of 
-         ``101`` documents and a maximum size of 16 mebibyte (MiB) for each subsequent batch. This
+         ``101`` documents and a maximum size of 16 mebibytes (MiB) for each subsequent batch. This
          option can enforce a smaller limit than 16 MiB, but not a larger
          one. If you set ``batchSize`` to a limit that results in batches larger than
          16 MiB, this option has no effect.