Improve code coverage for TreeSyntacticGroup

[MasseGuillaume]

Coverage Report

• TreeSyntacticGroup
  • [ ] Term.Xml
  • [ ] Term.Return
  • [ ] Term.Ascribe
  • [ ] Term.Try
  • [ ] Term.TryWithHandler
  • [ ] Term.PartialFunction
  • [ ] Term.While
  • [ ] Term.Do
  • [ ] Term.For
  • [ ] Term.ForYield
  • [ ] Term.Placeholder
  • [ ] Term.Eta
  • [ ] Term.Param
  • [ ] Type.Project
  • [ ] Type.Singleton
  • [ ] Type.Or
  • [ ] Type.Existential
  • [ ] Type.Lambda
  • [ ] Type.Method
  • [ ] Type.Placeholder
  • [ ] Type.Bounds
  • [ ] Type.Repeated
  • [ ] Type.ByName
  • [ ] Type.Var
  • [ ] Type.Param
  • [ ] Pat.Xml
  • [ ] Pat.Interpolate
  • [ ] Pat.Typed