message: Rethrow error if semantic token request is rejected.
diff: @@ -344,7 +344,7 @@ export class SemanticTokensFeature extends TextDocumentFeature<boolean | Propose
  return protocol2code.asSemanticTokens(result);
  }, (error: any) => {
  client.logFailedRequest(Proposed.SemanticTokensRequest.type, error);
  - return undefined;
  + throw error;
  });
  };
  return middleware.provideDocumentSemanticTokens
  @@ -368,7 +368,7 @@ export class SemanticTokensFeature extends TextDocumentFeature<boolean | Propose
  }
  }, (error: any) => {
  client.logFailedRequest(Proposed.SemanticTokensEditsRequest.type, error);
  - return undefined;
  + throw error;
  });
  };
  return middleware.provideDocumentSemanticTokensEdits
  @@ -392,7 +392,7 @@ export class SemanticTokensFeature extends TextDocumentFeature<boolean | Propose
  return protocol2code.asSemanticTokens(result);
  }, (error: any) => {
  client.logFailedRequest(Proposed.SemanticTokensRangeRequest.type, error);
  - return undefined;
  + throw error;
  });
  };
  return middleware.provideDocumentRangeSemanticTokens
  