Music disc ID names are inconsistent with other items

The item ids for music discs have the descriptor (the song title) after "music_disc" - for example, music_disc_pigstep.

This is inconsistent with most other items in the game, for example the new (also experimental) armor trim smithing templates (e.g. vex_armor_trim_smithing_template), spawn eggs (e.g. pig_spawn_egg), and all other blocks/items with colours or materials in their ids (blue_banner, oak_sign, chest_minecart, etc.).

Given these precedents, the correct name for music_disc_pigstep should be pigstep_music_disc, and likewise for the other music discs.