New feature request: ticks for minor breaks

[larmarange]

On some graphs, in particular when grids are not drawn, it would be relevant to add ticks for minor breaks.

Similar to annotation_logticks(), it could be relevant to have a function annotation_minorticks() to draw such minor ticks, or something similar.

[smouksassi]

Are you aware of this
https://teunbrand.github.io/ggh4x/articles/PositionGuides.html#minor-ticks

[larmarange]

I didn't know that but this exactly that.

[teunbrand]

I'd be happy to contribute that code for minor ticks in axis guides, however I think it makes more sense to implement #3329 first.