Rewrite "no face" in digging packet to a valid 1.8 value

[Beaness]

A correct fix for the issue that was being experienced in #629
This pr ensures the facing value is never an invalid value and always in the range 1.8 servers accept (0-5)

MC 1.7.10: (uses 255)

MC 1.8.9: (uses EnumFacing.DOWN equivalent with 0)

[florianreuth]

Ahh this makes sense

[florianreuth]

Or well, you should check for == 255 then instead of > 0, no?

[Beaness]

Or well, you should check for == 255 then instead of > 0, no?

Thought it was safer to just completely rewrite everything above > 5 as MC 1.8.9 only really knows 0-5.

The mc server itself does a mod operator on reading the enum which prevented crashes on normal spigot servers (as it wrapped around to a valid enumfacing) but on minestom this probably doesn't exist which caused the crash of that pr.

[Beaness]

(Another technical note for anyone reading: 1.7.10 uses -1 as "no face" too but since the byte is read as an unsigned byte this goes back to 255)