Ability to refer to a variable group as a dictionary or list

A common pattern in our recent questions is to define several versions of a block of text in separate variables, then put them into a list and select from them. At the moment, the list has to be hard-coded with the names of all the variables.

It would be convenient if there was a special option in the 'data type' drop-down called "Variable group as list/dictionary". You'd select a variable group, and it'd either collect all the variables in that group into a list, or into a dictionary with the variables' names as keys.

Locate the data type drop-down and the existing variable-group handling in the editor. Determine how a selected group could provide either a list of values or a dictionary keyed by variable names; done means both representations can be selected and populated without hard-coding each variable.

Written by the indexing model from the issue text.