Add a sans-serif j variant

[paolobolzoni]

(post 3.0) Add a variant j without the top serif

[be5invis]

There's already dotlessj.straight. I think you just need to export it in variants.toml.

[be5invis]

Like this:

[simple.v-j-straight]
tag = "cv98"
sampler = 'j'
description = '`j` without serif'
dotlessj = "straight"

[paolobolzoni]

Inspired by zyxw59's #140 (comment)