Document descriptions for color labels

[kofa73]

Please include a link to the Pull Request that you are documenting

For darktable-org/darktable#16139.

Tell us a little bit about this pull request

Added a short description mentioning the right-click to assign a description.

Note: is the label shown anywhere? I know it's shown in the tooltip (here: experiment):

But e.g. in filters, only the colour is shown:

Same for the filter:

[elstoc]

yes I think it's just in the tooltip. As I said in the PR, it seems pretty pointless functionality to me. It's probably worth mentioning that (the assigned name appears in the tooltip) as part of this PR.

[victoryforce]

yes I think it's just in the tooltip.

In the tooltip of buttons only, yes. Thanks for your attention, @kofa73! Indeed, it would be logical to add a custom description of the color labels in other places as well.

As I said in the PR, it seems pretty pointless functionality to me.

I personally don't use color labels much, but I know people who are very happy with this improvement.

Unlike rating stars, colors do not have any natural connection to the quality or status of the image. Each user invents this to their own taste, often experimenting to find the most useful model for themselves. A reminder of the semantics they settled on is a useful thing.

Yes, of course, implementing this through global settings was a suboptimal idea, here I fully support you.

By the way, Lightroom also supports assigning different semantics to color labels.

[kofa73]

OK. Anything I should change in the description? As it stands, I think it documents the current state. Please let me know if you something is blocking a merge.

[elstoc]

Yes I asked you to add some wording:

It's probably worth mentioning that (the assigned name appears in the tooltip) as part of this PR.

[kofa73]

Yes I asked you to add some wording:

OK, thanks; done.

[elstoc]

LGTM thanks