A language selector is the combination of one or many language identifiers
and language filters.
Note that a document selector that is just a language identifier selects all
documents, even those that are not saved on disk. Only use such selectors when
a feature works without further context, e.g without the need to resolve related
'files'.
Sample
let sel:DocumentSelector = { scheme: 'file', language: 'typescript' };
A language selector is the combination of one or many language identifiers and language filters.
Note that a document selector that is just a language identifier selects all documents, even those that are not saved on disk. Only use such selectors when a feature works without further context, e.g without the need to resolve related 'files'.