Is your feature request related to a problem? Please describe.

Tree generation (/tool tree, /forest, etc) don't have support for some of the newer tree types.

Describe the solution you'd like

The two new nether fungi (and possibly some other missing types?) should be added to TreeType and its generators.

Describe alternatives you've considered

A more generic feature placement tool would be nice, but outside the scope of the existing TreeType framework.

Additional context

Might need to check out "grow on" blocks (nylium etc) as well, I believe we check them explicitly somewhere.
Bukkit platform also has some tests which checks Bukkit's tree type enum that we need to validate.