bargap in barmode=relative

[nicolaskruchten]

If I make a multi-trace histogram with barmode set to "relative", I would expect the bargap to stay 0, like it does in "stack".

Per @alexcjohnson:

We should really coerce barmode first, then invoke this logic only for barmode !== 'group'. And of course update it when bar stackgroup becomes a thing…

[etpinard]

@antoinerg would you be interested in taking this one at some point this week?

[nicolaskruchten]

This was the link @etpinard dropped into Slack about where in the code it's happening:

plotly.js/src/traces/bar/layout_defaults.js

Line 52 in 0588483

coerce('bargap', (shouldBeGapless && !gappedAnyway) ? 0 : 0.2);