Importer: "Keep both" should be "keep all"

[RollingStar]

Problem

When importing duplicate albums, the importer will prompt to "keep both" if "ask" is set in the config.

beets/beets/ui/commands.py

Line 806 in bf9b43a

(u'Skip new', u'Keep both', u'Remove old', u'Merge all')

This is true even when you have 2+ duplicate albums already in your library and are trying to add another duplicate. For simplicity and clarity, it should be "keep all".

If we make the change, a few docs and comments will have to change too. Nothing major.

https://github.com/beetbox/beets/search?q=%22keep+both%22&unscoped_q=%22keep+both%22

[sampsyo]

Good call. Do you think it would be too crazy for it to dynamically switch between "keep both" (for 2) and "keep all" (for >=3)? Probably not necessary, just thought I'd wonder aloud to see if it seemed worthwhile. 😃

[RollingStar]

Good question. IMO, if more verbose comparison dialog is ever implemented (such as #2852), "keep all" will be more intuitive even with just 2 albums.