message: Add request failed error code
diff: @@ -22,6 +22,16 @@ export namespace LSPErrorCodes {
  */
  export const lspReservedErrorRangeStart: integer = -32899;
  + /**
  + * A request failed but it was syntactically correct, e.g the
  + * method name was known and the parameters were valid. The error
  + * message should contain human readable information about why
  + * the request failed.
  + *
  + * @since 3.17.0
  + */
  + export const RequestFailed: integer = -32803;
  +
  /**
  * The server cancelled the request. This error code should
  * only be used for requests that explicitly support being
  