Bool nestingExceptions(Pair<String, String> ex)
Arguments
ex: A pair of element names in "parent, child" order
Usage
Returns true if the nesting exception in the pair is allowed. This is used to add exceptions to the elements where pretendEmpty is true (for example, ("ul","li") returns true). Nesting exceptions are not made for the table elements, as editing these via addition of elements would be very error-prone - the specialised table editing functions in HTMLDocument should be used instead.
