#1259 PG: duplicate chapter "Pre defined symbols" leading to link errors

[Simon Sobisch]

I've worked around that in [r5714] by ignoring one of the entries - but that should be cleaned up as it is likely not a good idea to have it in both places (if we really want that, then possibly @include a common element that has the definition in either the table format (one occurrence) or the list item format (other occurrence) - but in any case the subsection need to be named different in one place to not break links.

Side note @vcoen: that commit fixed a bunch of other "technical" issues, please have a look