Describe the bug
So when i added music for the wither fight, it also detected wither skeletons for some reason. Might be cause it's name starts with wither.

To Reproduce
Steps to reproduce the behavior: Just add music to the wither

That would be correct as resource_name parameters are allowed to partially match in most cases and minecraft:wither is contained in minecraft:wither_skeleton. However ,the mob trigger is also able to check for display names which must match exactly. Setting the resource_name = [ "Wither" ] should work for the display name, but since the wither is also a boss you can utilize the BOSS case like resource_name = [ "BOSS" "Wither" ].

Boss whitelisting also follows the partial matching/exact matching conventions between the mob id & display names with the caveat that there needs to be a boss bar so it shouldn't pick up wither skeletons regardless.

While this isn't an issue, it is related to an enhancement planned for 7.0 regarding the resource_name parameter so I'll leave this open.