C++: Improve QLDoc

Author: jketema

cpp/ql/lib/semmle/code/cpp/Class.qll

@@ -1099,12 +1099,12 @@ class ProxyClass extends UserType {
   /** Gets the location of the proxy class. */
   override Location getLocation() { result = this.getTemplateParameter().getDefinitionLocation() }
 
-  /** Gets the template parameter for which this is the proxy class. */
+  /** Gets the template parameter for which this is the proxy class, if any. */
   TypeTemplateParameter getTemplateParameter() {
     is_proxy_class_for(underlyingElement(this), unresolveElement(result))
   }
 
-  /** Gets the decltype for which this is the proxy class. */
+  /** Gets the decltype for which this is the proxy class, if any. */
   Decltype getDecltype() { is_proxy_class_for(underlyingElement(this), unresolveElement(result)) }
 }