Merge pull request OAI#1231 from hkosova/json-request-fix

Fixed JSON request example in "Key Expression"

Author: RobDolinMS

versions/3.0.md

@@ -1838,10 +1838,10 @@ For example, given the following HTTP request:
 POST /subscribe/myevent?queryUrl=http://clientdomain.com/stillrunning HTTP/1.1
 Host: example.org
 Content-Type: application/json
-Content-Length: 123
+Content-Length: 187
 
 {
-  "failedUrl" : "http://clientdomain.com/failed"
+  "failedUrl" : "http://clientdomain.com/failed",
   "successUrls" : [
     "http://clientdomain.com/fast",
     "http://clientdomain.com/medium",