This commit changes the behavior of the "Add" and "Create" collection
operators (found in the property editor and under ctrl-G respectively)
so that the new collections are added to the scene collection heirarcchy
as children of the active collection.
Without this patch, when collections are created with these methods they
are not linked to the current scene. This make it necessary to switch to
the "Data API" or "Scene" display modes in the outliner, or look in the
"Collections" panel in the property editor to see that the operator
actually worked. In fact, a common piece of feedback from users about
these operators (especially ctrl-G) is that they don't work!
Besides that, there are a few more reasons to change the behavior:
- It's consistent with the "Link to Collection" operator, which actually provides the option to create a new collection.
- It creates a teachable moment in the outliner when the user sees clearly that objects can be in more than one collection.
- It provides more visual feedback, which can be a starting place for improving the "grouping" behavior of collections.
One downside of this change is that there may end up being more clutter
in the outliner, as new collections created with these methods will be
linked to the scene, and therefore displayed, by default. However, the
outliner is meant to display these sort of things, and the collections
can be easily collapsed, or even moved inside another collection.
The naming and tooltips of these operators are also slightly adjusted
to be more clear about what they actually do.
