Fix REST example how to confirm adding many reviewers

The flag that has to be set to confirm adding many reviewers is named
'confirmed' and not 'confirm'.

Change-Id: Id867fb38b436f25ed1862b493bc5eb2cc40c495b
Signed-off-by: Edwin Kempin <edwin.kempin@sap.com>
diff --git a/Documentation/rest-api-changes.txt b/Documentation/rest-api-changes.txt
index 72bd4dd..2ce7f3c 100644
--- a/Documentation/rest-api-changes.txt
+++ b/Documentation/rest-api-changes.txt
@@ -926,7 +926,7 @@
 ----
 
 To confirm the addition of the reviewers, resend the request with the
-`confirm` flag being set.
+`confirmed` flag being set.
 
 .Request
 ----
@@ -935,7 +935,7 @@
 
   {
     "reviewer": "MyProjectVerifiers",
-    "confirm": true
+    "confirmed": true
   }
 ----