[texinfo 7.2]
The documentation in the 'Direction' section of 'texi2any_api' says
_Index_
The first output unit with ‘@printindex’.
This is not ideal. Assuming that a large document has multiple
indices, the most general index is normally the last one, not the
first. Sometimes, however, it might even happen that it is in the
middle, like this:
Index of commands
Index of concepts <--
Index of persons
I thus suggest to make it configurable to which index the 'Index'
direction points to – I can naively imagine to add an optional
argument to `format_navigation_button` (and probably other commands)
that takes the argument of the `@printindex`, for example,
```
my_index = {'direction' => 'Index',
'index' => 'cp'};
format_navigation_button($converter, my_index);
```
Note that my Perl abilities are limited (and I have zero experience
with `texi2any`'s API); I'm sure there are better possibilities to
handle this.
Werner
