fix: import parser properly delegates to resource location parser

[TheWii]

I noticed that the bolt:import parser uses parsers["resource_location_or_tag"] to get the resource_location_or_tag parser (instead of using the delegate function), making it impossible to be overridden.

[vberlier]

Yeah I think using delegate would be desirable here but you need to wrap it with DisableInterpolationParser since bolt overrides resource_location_or_tag to enable interpolation.