[api-ref] Add request examples for share replica APIs

Samples illustrate how to send POST requests to the
/v2/share-replicas/{replica_id}/action to initiate
share replica promotion and resync actions.

Change-Id: I6c4890909406668322e387466620d591f161a93a
Signed-off-by: Goutham Pacha Ravi <gouthampravi@gmail.com>

api-ref/source/samples/share-replica-promote-request.json

@@ -0,0 +1,3 @@
+{
+    "promote": null
+}

api-ref/source/samples/share-replica-resync-request.json

@@ -0,0 +1,3 @@
+{
+    "resync": null
+}

api-ref/source/share-replicas.inc

@@ -154,6 +154,12 @@ Request
    - project_id: project_id_path
    - share_replica_id: share_replica_id_path
 
+Request example
+---------------
+
+.. literalinclude:: samples/share-replica-promote-request.json
+   :language: javascript
+
 
 Resync share replica
 ====================
@@ -187,6 +193,13 @@ Request
    - share_replica_id: share_replica_id_path
 
 
+Request example
+---------------
+
+.. literalinclude:: samples/share-replica-resync-request.json
+   :language: javascript
+
+
 List share replicas
 ===================