doc: fix doc

Signed-off-by: Darshan Sen <raisinten@gmail.com>

Author: RaisinTen

doc/api/diagnostics_channel.md

@@ -1247,7 +1247,9 @@ Emitted when a stream is received on the client.
 
 * `stream` {ClientHttp2Stream}
 * `writev` {boolean}
-* `data` {Buffer | string | Array\<Buffer | {chunk: Buffer|string, encoding: string}>}
+* `data` {Buffer | string | Buffer\[] | Object\[]}
+  * `chunk` {Buffer|string}
+  * `encoding` {string}
 * `encoding` {string}
 
 Emitted when a chunk of the client stream body is being sent.