JavadocLeadingAsteriskAlign should be able to ignore invalid html

[MateuszStefek]

The following Javadoc has all asterisks aligned correctly, but the JavadocLeadingAsteriskAlign fails.

	/**
	 * Foo bar bla bla <code>code<code> foo bar
	 */
	public static void x() {

07:58:07 [main] [ERROR] MyClass.java:[229] (javadoc) JavadocLeadingAsteriskAlign: Javadoc comment at column 20 has parse error. Missed HTML close tag 'code'. Sometimes it means that close tag missed for one of previous tags.

<property name="violateExecutionOnNonTightHtml" value="false" /> doesn't help.

There's a mistake in the html, but I think HTML validation should be a separate check.