This adds a new subpanel to the geometry nodes modifier which is just
used to display information about used attributes.
* A new panel is used because adding this information anywhere else
clutters the ui too much imo.
* The general layout is similar to that in the tooltip. I found it to be more
trouble than it's worth to share this code.
Possible future improvements:
* Don't show the panel if there are no used named attributes.
* Add some heuristics to determine which named attributes the user does
not have to care about because they are only used in the node group
and don't affect anything else.
Differential Revision: https://developer.blender.org/D14701
0178e694b7