Update info docs with two buffer limit metrics. (#2520)

Add explains about "client_query_buffer_limit_disconnections" and
"client_output_buffer_limit_disconnections".

Correct "reply_buffer_shrinks" and "reply_buffer_expands" name.

commands/info.md

@@ -310,8 +310,10 @@ Here is the meaning of all fields in the **stats** section:
 *   `total_writes_processed`: Total number of write events processed
 *   `io_threaded_reads_processed`: Number of read events processed by the main and I/O threads
 *   `io_threaded_writes_processed`: Number of write events processed by the main and I/O threads
-*   `stat_reply_buffer_shrinks`: Total number of output buffer shrinks
-*   `stat_reply_buffer_expands`: Total number of output buffer expands
+*   `client_query_buffer_limit_disconnections`: Total number of disconnections due to client reaching query buffer limit
+*   `client_output_buffer_limit_disconnections`: Total number of disconnections due to client reaching output buffer limit
+*   `reply_buffer_shrinks`: Total number of output buffer shrinks
+*   `reply_buffer_expands`: Total number of output buffer expands
 *   `eventloop_cycles`: Total number of eventloop cycles
 *   `eventloop_duration_sum`: Total time spent in the eventloop in microseconds (including I/O and command processing)
 *   `eventloop_duration_cmd_sum`: Total time spent on executing commands in microseconds