Use arena class "config names" in /ma autogenerate.

Swaps the weird "camel casing" approach in the autogenerate command out
with simply using the "config name" of the arena classes when creating
class selection signs.

This fixes the breaking change to how classes are resolved in a previous
commit, but only in future arena generation procedures. Arena generated
before this change may still contain broken class signs.

changelog.md

@@ -25,6 +25,7 @@ These changes will (most likely) be included in the next version.
 - The Root Target ability now uses potion effects (slowness, slow falling, and negative jump boost) instead of repeated teleports. This should make for a smoother root experience.
 - Permissions for arenas and classes are now based on "slugs". It is now possible to configure permissions for arenas and classes with multi-word names (including "My Items"). Check the Permissions page on the wiki for details.
 - Commands that resolve class names now consistently resolve and tab complete "slugs" instead of arbitrarily "squashed" names. This greatly improves support for multi-word names.
+- The class signs generated by the `/ma autogenerate` command now use class names from the config-file instead of arbitrarily "squashed" names.
 - Using `spectate-on-death: true` no longer forces players out to their join location/exit warp before moving them to the spectator area. This should prevent "jumpy" behavior in multi-world setups.
 - Players should now properly respawn at the spectator area rather than at world spawn on servers with plugins that override respawn locations.
 - Config-files with missing `pet-items` nodes no longer errors. A missing `pet-items` node in `global-settings` is treated as empty, i.e. no pet items will be registered.