Description:

The SWI-Prolog online documentation has some odd quirks:

- Cross-references are replaced with «??»
- Literature reference are replaced with «?»
- Example code boxes are missing newlines or have adjacent lines interspersed
- In-line code formatting is broken when it contains quotes or underscores
(e.g., «representation_error('FD_SETSIZE')» has «'FD_» formatted bold, «SETSIZE'»
underlined)

IIRC the online manual is generated from LaTeX sources, perhaps something is going
wrong during the build there; at least the replacement of references with «??» is
reminiscent of LaTeX processing errors.

I reported similar issues to upstream a while ago (https://github.com/SWI-Prolog/swipl/issues/7),
but they were unable to reproduce this. Note that the screenshot might have been taken
for a build from the AUR -devel package; the weird box glyphs don’t show up in the
community package.

Additional info:
* swi-prolog 7.6.4-1

Steps to reproduce:
1. Invoke «swipl»
2. Issue «help.»