Changes

Specify that chapter introductions are non-normative.

Split of terminology as separate section.

Remove normative text (already part of equations-chapter),
and replace it with some relevant introduction.

No need to mark the start as non-normative anymore.

Split of normative part.

Reformulate to have a non-normative introduction, followed by an actual normative part.

Switch from table to item-list after latexml bug was corrected.

Fix reference to table.

Mark entire introduction to array chapter as non-normative.
As far as I could see all the normative parts were duplicated from the chapter
and thus redundant.

Move non-normative motivation for package to start of chapter,
and move up most definitions as discussed.

Reorder sections in package-chapter as discussed.

Remove extra label.

Use \emph instead of all upper case letters

Address GitHub warning about incorrect pair of double quotes

Remove nonnormative unclear text

Rewrite synchronous rationale to be positive (#2656)

* Move synchronous introduction right under chapter; and rewrite slightly.
* Reformulate the rationale to be positive.
* With corrected review comments.
Co-authored-by: Henrik Tidefelt <henrikt@wolfram.com>

Closes #2512