Fix display of superclass methods in completion

E.g.:
groovy:000> class Foo{}
===> true
groovy:000> Foo.<tab>

Before: super$1$xyz methods apper
after: methods appear under their name
Complete CustomFunctinos.

Example:
groovy:000> class BarFooBaz{}
===> true
groovy:000> Bar<tab>

Before: No completion
After:  groovy:000> BarFooBaz