Pazi weighting of matchers vs frecency is icky

[euank]

I think the weighting is a bit bad.

The relevant code is:

pazi/src/frecent_paths.rs

Lines 174 to 176 in 69d54c0

	.filter_map(move |m| match m.matches(item.0, filter) {
	Some(v) => Some((item.0, v * 0.8 + item.1 * 0.2)),
	None => None,

One obvious case this does poorly in is the certs and cert-manager folders I have. Even when my cert-manager folder has a higher frecency, typing z cert drops me in certs because the substring matcher weights that so much more highly.

I think a series of unit tests could help define what the right thing is, but at the very least tweaking the weights a bit for now is a good first step.