Update docs to use async/await (#667)

* [docs] update readme and examples to use async/await

* [apis] regenerate (including updated examples)

docs/_examples/suggest.asciidoc

@@ -1,17 +1,18 @@
 .Return query terms suggestions (“auto-correction”)
 [source,js]
 ---------
-client.suggest({
-index: 'myindex',
-body: {
-  mysuggester: {
-    text: 'tset',
-    term: {
-      field: 'title'
+const response = await client.suggest({
+  index: 'myindex',
+  body: {
+    mysuggester: {
+      text: 'tset',
+      term: {
+        field: 'title'
+      }
     }
   }
-}
-}, function (error, response) {
+});
+
 // response will be formatted like so:
 //
 // {
@@ -30,5 +31,5 @@ body: {
 //     }
 //   ]
 // }
-});
----------
+
+---------