Enhance 10.3.3. Multiple event qualifiers section

While the current spec is in fact correct, it is quite hard to decipher what it is actually trying to convey.

Elsewhere in the spec, we talk about subsets of qualifiers while here we don't. There is a code sample and a sentence saying "Then this observer method will only be notified if all the observed event qualifiers are specified when the event is fired:"
This can be interpreted as:

• "I must fire an event with exactly the same qualifiers as this observer has in order to notify it" (wrong assumption - it can have more qualifiers)
• "I must fire an event which will contain at least the same qualifiers as this observer has in order to notify it" (correct - yet not so obvious)

I will try to come up with some improvement to make this clear. As it is, it always takes me several reading to soak it in.