Create descriptions of all cross-references found in the given document. These descriptions are
gathered by the IndexManager and stored in the global index so they can be considered when
a document change is reported by the client.
The document in which to gather cross-references.
OptionalcancelToken: CancellationTokenIndicates when to cancel the current operation.
Language-specific service to create descriptions of all cross-references in a document. These are used by the
IndexManagerto determine which documents are affected and should be rebuilt when a document is changed.