Rust: Fix character in qhelp

Co-authored-by: Geoffrey White <40627776+geoffw0@users.noreply.github.com>

Author: paldepind

rust/ql/src/queries/security/CWE-311/CleartextTransmission.qhelp

@@ -36,7 +36,7 @@ practices into place.
 
 <li>
   OWASP Top 10:2021:
-  <a href="https://owasp.org/Top10/A02_2021-Cryptographic_Failures/">A02:2021 � Cryptographic Failures</a>.
+  <a href="https://owasp.org/Top10/A02_2021-Cryptographic_Failures/">A02:2021 - Cryptographic Failures</a>.
 </li>
 <li>
   OWASP: