Allow many more aspects of the generated page to be parameterized, and add a useful usage message.  Use 'mkmodindex --help' to display it.
Allow many more aspects of the generated page to be parameterized, and
add a useful usage message.  Use 'mkmodindex --help' to display it.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator