Rust: Fix grammar and typos

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: paldepind

rust/ql/src/change-notes/2025-11-24-xss-query.md

@@ -1,4 +1,4 @@
 ---
 category: newQuery
 ---
-* Added new a query `rust/xss`, to detect XSS security vulnerabilities.
+* Added a new query `rust/xss`, to detect XSS security vulnerabilities.

rust/ql/src/queries/security/CWE-079/XSS.qhelp

@@ -36,7 +36,7 @@ included in the response:</p>
   (Cross Site Scripting) Prevention Cheat Sheet</a>.
 </li>
 <li>
-  WiMISSING: Alert[rust/xss]kipedia: <a href="http://en.wikipedia.org/wiki/Cross-site_scripting">Cross-site scripting</a>.
+  Wikipedia: <a href="http://en.wikipedia.org/wiki/Cross-site_scripting">Cross-site scripting</a>.
 </li>
 <li>
   OWASP: