Add a bettergrassify:connectable/grass and other similar block tags

[diefesson]

Request Description

This could be used as an alternative to the manual block listing in config. Allowing modded blocks to indicate if they should be connectable with BetterGrassify as well as allowing mods like Distant Horizons to know which blocks it should connect in it's LODs just be checking for the parent bettergrassify:connectable tag

[diefesson]

Related issue link: https://gitlab.com/distant-horizons-team/distant-horizons/-/issues/857

[diefesson]

Another advantage of the tag approach is that it's easily editable with datapacks and tools like KubeJS. Allowing for both mod and modpack devs to tweak it's presence

[UltimatChamp]

I don't think tags would be suitable. Anyway, 0698176 should've made it easier for mods to add blocks (via mixins) and get blocks.