Add a definition for the @throws block tag

[octogonz]

Add the @throws tag as discussed in RFC 171

Example syntax:

   /**
    * Retrieves metadata about a book from the catalog.
    *    
    * @param isbnCode - the ISBN number for the book
    * @returns the retrieved book object
    *
    * @throws {@link IsbnSyntaxError}
    * This exception is thrown if the input is not a valid ISBN number.
    *
    * @throws {@link book-lib#BookNotFoundError}
    * Thrown if the ISBN number is valid, but no such book exists in the catalog.
    *
    * @public
    */
    function fetchBookByIsbn(isbnCode: string): Book;

@aciccarello FYI