Support multi-valued tags

[deluan]

Hey @dhowden, have you considered supporting multi-valued tags? I started looking deeper in this package's codebase, and I think we could introduce it without breaking compatibility, by adding methods like

Values(name tag.Name) []string // this returns all values for a given tag, with a normalized (enum) name
Artists() []string
AlbumArtists() []string
Genres() []string
PictureTypes() []string
Pictures(type string) *Picture
RawValues() map[string][]any
...

Actually I just implemented Pictures/PictureTypes in my fork, to investigate/resolve an issue in my music server (navidrome/navidrome#3254).

Any thoughts? I can try to implement this if you feel it is a good addition.

By the way, here's my change implementing multiple pictures, but just for Vorbis for now: deluan@dfe5e6e

[dhowden]

Hey!

Great idea! I hesistate to make it an interface, since we then have to implement it on all the tag readers.

We can certainly start to add the methods to the different tag reader implementations and then see where we get to - what do you think?

P.S. I disabled github notifications a while back due to a noisy org I was added to :(. I'm behind now with most non-work correspondence.