FABN-987: Update JSDoc for ProposalResponseObject

Clarify that index 0 is a mixed array containing both ProposalResponse
and/or Error objects.

Change-Id: I9e8906f871b5ab6ed4398cde7eeeb9e8b52f4780
Signed-off-by: Mark S. Lewis <mark_lewis@uk.ibm.com>

fabric-client/lib/Client.js

@@ -1009,8 +1009,9 @@ const Client = class extends BaseClient {
 	 * standard array of objects.
 	 *
 	 * @typedef {array} ProposalResponseObject
-	 * @property {ProposalResponse[]} index:0 - Array of ProposalResponse objects from the
-	 *           endorsing peers
+	 * @property {Array<(ProposalResponse|Error)>} index:0 - Array where each element is either a ProposalResponse
+	 *           object (for a successful response from the endorsing peer) or an Error object (for an unsuccessful
+	 *           peer response or runtime error).
 	 * @property {Object} index:1 - The original Proposal object needed when
 	 *           sending the transaction request to the orderer
 	 */