Code looks good to me.

However we do need to decide what we want to happen.
if:
Filter.regex('one') | Filters.regex('two')
and
message.text = 'one and two'
Do we want len(context.matches)==1 or len(context.matches)==2
The first is more pythonic in a sense that it is in line with the way python handles and and or and this PR changes behavior into that. However it might need some rewording on the context.matches docstring maybe?

I'd say that len(context.matches)==1 is the better option as I'm pretty sure we make a direct comparison between our bitwise operators and and or not in our docs.

Good idea about adding it to documentation. Maybe even adding a note directly in Filters.regex would be a good idea?