Fix completion with backticks, underscores, numbers#10500

Merged

cartermp merged 3 commits intodotnet:mainfrom zanaptak:completion-span

Nov 25, 2020

+123-10

Commits on Nov 18, 2020

Make completion span include backticks and ident characters
zanaptak
committed

Commits on Nov 22, 2020

Use Tokenizer for backtick identifiers
zanaptak
committed

Commits on Nov 25, 2020

Add tests for GetDefaultCompletionListSpan
zanaptak
committed