Remove duplicated CWE in security tag

Author: h3ku

csharp/ql/src/experimental/CWE-099/TaintedWebClient.ql

@@ -1,18 +1,16 @@
 /**
  * @name Uncontrolled data used in a WebClient
- * @description The WebClient class allow developers to request resources,
+ * @description The WebClient class allows developers to request resources,
  *              accessing resources influenced by users can allow an attacker to access local files.
  * @kind path-problem
  * @problem.severity error
  * @precision high
  * @id cs/webclient-path-injection
  * @tags security
  *       external/cwe/cwe-099
- *       external/cwe/cwe-022
  *       external/cwe/cwe-023
  *       external/cwe/cwe-036
  *       external/cwe/cwe-073
- *       external/cwe/cwe-022
  */
 
 import csharp