Improve incoming call for typeclass and type family instance

[July541]

Now the incoming call about type class/family will jump to the corresponding instance.

class F a where
  f :: a
instance F Bool where
  f = x
instance F Int where
  f = y

x = True
y = 3

Previously, If we request an incoming call for x, it will jump to line 2, but now it will go to line 4, the more direct result.

[jneira]

many thanks for the fix

[July541]

In the latest commit, I replaced constant delay with retry.