PDF ToC adds “Chapter :” prefix to "appendices" navtitle

[infotexture]

As discussed in #2092 (comments), an <appendices> element with a @navtitle attribute such as

  <appendices navtitle="Appendices">

appears in the PDF ToC with a “Chapter :” prefix before the @navtitle text.

Chapter : Appendices ………… [page]

The prefix should be removed to show only the navtitle and align presentation with the PDF bookmark hierarchy.

[robander]

Testing this ... in the actual content, you still get an "Appendix" page heading above the appendices, without an appendix number, which is ... odd. Attaching a sample with 3 maps, using each of
<appendices>
<appendices navtitle="Appendix container">
<appendices navtitle="appendices.dita">

I ... suspect that the "Appendix" heading is a bad one, and should come from a new variable for appendices, but right now I'm not ambitious enough to add that support, so just working on the requested fix.

2695.zip

[robander]

Fixed with aa94392