mutt: speed up filtering
mutt: speed up filtering

Prefer subselection (chaining) over composition with operators (*),
because it is way faster in the case where there are no matches for the
initial condition (which is usually the case).

wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent,wincent/wincent