Lead Improvements (With TGN101)

I don't like accidentally hitting my horse while mining. The first post about "Lead Improvements" is about HUD made by someone else, mine's about for gameplay.

In this idea, Broken leads should return leads to you, even if you unleaded that animal. Leads can go down to zero, but you obviously can't use more leads if it reached down to zero. But you can use the leads (even if the value is zero) on the fence post for free, but will disappear from your inventory if you have 0 leads in your inventory.

If you have an animal leaded to you, you can still mine blocks, even if they're in your way. You can't accidentally kill them while leaded to you.