punching a blackboard/greenboard changes the formspec

[fluxionary]

after placing:

if you then punch the board, and right-click again:

note that in the 2nd form, the "font" button doesn't do anything.

[Niklp09]

https://github.com/Archtec-io/display_modpack/commit/fbbfc07e1259966972a17361bcb74edc7ef21b12