Support enclosing_range for call hierarchy

[varungandhi-src]

Requested by customer, original Slack thread

They'd like to do some tracing around how certain dependencies of theirs are used

With our current index, we're able to find that SqlClient#Update. is called from this file, but unless we do an additional AST parse to link it to UpdateUsername, we're not able to trace further up the tree. Now if the type for (my/services/model/helper#UpdateUsername().) had its enclosingRange defined, we would be able to use JUST the index to follow this call up into the service, eventually over to a service controller or main function somewhere. (eg: we can just keep walking up until no more enclosing ranges exist

[CatherineGasnier]

We'd also need this

[podtserkovskiy]

@varungandhi-src @jupblb Could you please take a look on #172 and scip#343?