Adding names to geometry sets has some benefits:

• Makes it easier to understand the spreadsheet.
• The names could be used on export or when the Make Instances Real operator is used.

This patch isn't ready yet.

• Find a decent looking layout for the tooltip for nested instances.
• Show the more informative tooltip in socket inspection as well (that's a bit more tricky, because we don't store the entire geometry for every socket).
• Maybe pre-fill the name in Object/Collection Info nodes. Currently there is an update issue. The depsgraph is (probably intentionally) not updated when a collection name changes.
• Hiding label from string socket in Set Geometry Name node needs a ui fix.