Allow nested short hand for lists

[mattklein123]

Is your feature request related to a problem? Please describe.
Short hand notation for structs (no braces for internal references) is a very nice feature. I find myself wanting this same capability for lists to reduce verbosity.

Describe the solution you'd like

Take a config like this:

cds.#cluster & {
		name: "foo"
		load_assignment: endpoints: [{
			lb_endpoints: [{
				endpoint: address: socket_address: {
					address:    "foo.svc.cluster.local"
					port_value: 8088
				}
			}]
		}]
	}

And allow it to be written as:

cds.#cluster & {
		name: "foo"
		load_assignment: endpoints[0]: lb_endpoints[0]: endpoint: address: socket_address: {
			address:    "foo.svc.cluster.local"
			port_value: 8088
		}
	}

Describe alternatives you've considered
Write it out more verbosely per above.

Additional context
None. I tried to look for an existing issue on this and could't find one. Sorry if I missed it. Thank you for a great tool!

[mpvl]

The query proposal (#165) alludes to allowing the following shorthand:

load_assignment: endpoints: 0: lb_endpoints: 0: endpoint: address: socket_address: {
			address:    "foo.svc.cluster.local"
			port_value: 8088
		}

The intention is to do this at some point. Note that this would seemingly be ambiguous to allowing integer maps as well. However, CUE internally lists and maps are treated identically, so a list would just be a constraint on the "totalness" of the map. So, technically, in the above example one would still need to define somewhere that the endpoints fields are lists. Presumably that is done in cds.#cluster already though.

So it is these details that need to be worked out to make that work, but basically this is being considered.

[mattklein123]

So it is these details that need to be worked out to make that work, but basically this is being considered.

Awesome thank you!