Auto-completion fail on thisContext

[jecisc]

If Pharo 8 if you open a playground and type thisContext you get an error with the new autocompletion.

CompletionProducer(Object)>>doesNotUnderstand: #visitThisContextNode:
RBThisContextNode>>acceptVisitor:
CompletionProducer>>completionListForNode:
CompletionModel>>initEntries
CompletionModel>>entries
CompletionModel>>notEmpty
NECMenuMorph>>selected:
NECMenuMorph>>narrowCompletion
NECMenuMorph>>setController:position:
NECMenuMorph class>>controller:position:
CompletionController(NECController)>>openMenuFor:
CompletionController(NECController)>>openMenu