Move PROBE_FIELD to module scope (#3318)
Move PROBE_FIELD to module scope (#3318)

sampsyo/beets,SusannaMaria/beets,jackwilsdon/beets,jackwilsdon/beets,beetbox/beets,shamangeorge/beets,shamangeorge/beets,shamangeorge/beets,ibmibmibm/beets,beetbox/beets,ibmibmibm/beets,shamangeorge/beets,beetbox/beets,SusannaMaria/beets,SusannaMaria/beets,sampsyo/beets,jackwilsdon/beets,ibmibmibm/beets,sampsyo/beets,sampsyo/beets,SusannaMaria/beets,jackwilsdon/beets,ibmibmibm/beets,beetbox/beets