find all references to an entity
Ref=main.adb 4 6
Ref=a.adb 4 14
Ref=a.adb 7 8
Ref=b.adb 5 9
Parameters: 
   Param=a at a.ads: 2: 21
   Param=c at a.ads: 2: 24
   Param=f at a.ads: 2: 37

Idem, but print list of subprograms that call entity
main (main.adb 2 11) -> proc1 (a.ads 2 14)
b (b.ads 1 9) -> proc1 (b.ads 2 14) -> proc1 (a.ads 2 14)
Parameters: 
   Param=a at a.ads: 2: 21
   Param=c at a.ads: 2: 24
   Param=f at a.ads: 2: 37

Idem, for another entity
main (main.adb 2 11) -> proc1 (b.ads 2 14)
a (a.ads 1 9) -> proc1 (a.ads 2 14) -> proc1 (b.ads 2 14)
a (a.ads 1 9) -> proc2 (a.ads 3 14) -> proc1 (b.ads 2 14)
