Rebuild Index for PDF Edition

[tajmone]

Currently the AsciiDoc port of The Hugo Book has no Index, because it only affects DocBook/PDF format.

At some point in the future, it would be good to rebuild the original Index of the book, for the sake of PDF editions; also, there might exist extension to add index-support to the HTML5 backend, so it's worth looking into it.

• INDEX (supported only in PDF format):
  • Rebuild original Index of the Word/PDF edition.
  • Try to find an extension to add index-support to the HTML5 backend.