code: public void setExtension(/* @Nullable */ JvmFormalParameter parameter, EObject sourceElement, boolean value) {
  		if (parameter == null)
  			return;
  		internalSetExtension(parameter, sourceElement, value);
  	}
docs: Adds or removes the annotation {@link Extension @Extension} from the given parameter. If the annotation is
  already present, nothing is done if {@code value} is {@code true}. If it is not present and {@code value}
  is {@code false}, this is a no-op, too.
  
  @param parameter the parameter that will be processed
  @param sourceElement the context that shall be used to lookup the {@link Extension annotation type}.
  @param value <code>true</code> if the parameter shall be marked as extension, <code>false</code> if it should be unmarked.