Is your feature request related to a problem? Please describe.
When assigning the same audio file to a bunch of music discs, it can be tedious to repeatedly switch to new discs and re-enter commands.

Describe the solution you'd like
In my opinion, it would be a really neat feature to be able to assign the same audio file to multiple discs at once. I envision filling up a shulker box with music disks that I want to overwrite, holding that shulker in hand instead of an individual music disk, and then running the command once to batch-apply the audio file to each disc in the box.

Describe alternatives you've considered
Alternative solution could include some sort of separate batch command to act on all discs in a player's inventory. But I think it's most elegant to craft boxes of discs at a time to save on inventory management headaches.

Additional context
I am a fan of Hermitcraft and how their entertaining videos have been elevated to a new level with your audio mod. I specifically envisioned this feature idea when watching TangoTek's live streams and seeing how he will need to generate tons of custom music disks for Season 9's Decked Out 2. For his card sounds he will need something like 30-40 different audio files each applied to approximately 28 music discs.

I am not super proficient at Java, but I'm hoping implementation of this feature would only require adding a check for shulker box instead of music disc in the player's hand and then iterating through the box contents to apply the audio assignment function to each music disc item.

Easier said than done I'm sure! Thank you for considering!