Add output-options as alias of output_options
output_options is the only syntax entry using _ vs -: as explained in #2904 (comment 379090) we can easily make output-options an alias of output_options in flex (.ll) files.
output_options is the only syntax entry using _ vs -: as explained in #2904 (comment 379090) we can easily make output-options an alias of output_options in flex (.ll) files.