Content Assist and no context node for cross references in empty document

[cdietrich]

given the grammar

entry Model:
    ref=Ref
;

// in our zoo these will be provided by another grammar
interface Definition {
    name: string
}

Ref: define=[Definition:ID];

when doing autocompletion for the Ref nothing will happen in an empty document as context.node is undefined.

this is cause here:

langium/packages/langium/src/lsp/completion/completion-provider.ts

Line 299 in 3b007c2

tokenOffset: nextTokenStart,

without a node scoing wont be called.

i wonder why not simply use document.parseResult.value