Add mini-curve-display-hints extension.

[roelofvkr]

This extension allows the plugin to optionally query the host for hints as to how a curve of a certain kind will be displayed.

The idea is that all mini curves within the host can display within the same range to provide a more unified experience.

[baconpaul]

I like this idea, but since mini curve is still in draft, any reason we can't consolidate this into mini curve for 1.3?

[roelofvkr]

@abique and I have talked about this and we chose to do this with the idea that it's an optional interface for hosts to implement, rather than an essential part of the mini curve extension. That said, I am not strongly opposed to consolidating it into one extension.

[abique]

Yes I think this could go into the mini curve ext, I take care of it.
Thanks 👍