Support call hierarchy on pattern matching

[July541]

This pr includes:

1. Now we can request call hierarchy on pattern matching items.
2. Null result should return Right Nothing, previous Right (Just []) and Left Error will all encounter internal errors while the new version(I'm not sure which one, it works will before) VSCode process the data, see Log(Remote Extension).

eg.

f 1 = 1
f 2 = 2

Request on line 2 will return empty before, but now it works as expected.

[jneira]

Great follow up, as all of your recent work here, many thanks again!

[Ailrun]

Awesome, thank you for the update!