Rust: Fix qhelp.

rust/ql/src/queries/security/CWE-696/BadCtorInitialization.qhelp

@@ -5,7 +5,7 @@
 <overview>
 
 <p>
-Calling functions and methods in the Rust <code>std</code> library from a <code>#[ctor]</code> or <code>#[dtor]<code> function is not safe. This is because the <code>std</code> library only guarantees stability and portability between the beginning and end of <code>main</code>, whereas <code>#[ctor]</code> functions are called before <code>main</code>, and <code>#[dtor]</code> functions are called after it.
+Calling functions and methods in the Rust <code>std</code> library from a <code>#[ctor]</code> or <code>#[dtor]</code> function is not safe. This is because the <code>std</code> library only guarantees stability and portability between the beginning and end of <code>main</code>, whereas <code>#[ctor]</code> functions are called before <code>main</code>, and <code>#[dtor]</code> functions are called after it.
 </p>
 
 </overview>