fix: Remove super calls from implicit enum constructors

[I-Al-Istannen]

The context

This aims to fix #4758 by removing the super call from implicit enum constructors.

The problem

For some reason JDT inserts a super() call in implicit enum constructors. This is likely because the model spoon transforms is not low-level enough and traversed before JDT converts it into a String, int constructor. Explicit super calls are forbidden as java.lang.Enum subclasses are permitted to delegate to the Enum constructor in whatever way they like.

The constructor is implicit so this isn't technically illegal, but it doesn't really make much sense as explicit constructors can never contain such a call. Additionally, the Enum class from the standard library has a "String, int" constructor, rendering the parameterless supercall semantically invalid.

The proposed fix

We just remove the call to make it a bit more consistent.

[MartinWitt]

LGTM will merge. It's always fascinating how much attention you pay to small details like this.