Scoping of decorations to layout element

A note here concerning a minor tweak to scoping that I’ve included in
citeproc-js. For elements that accept formatting, the normal
behaviour is to exclude affixes from the scope of the formatting
decorations, so that you don’t (for example) get italicized commas and
parens when using prefix="(" or suffix=").", say.

Extrapolating from a user request in the following thread, I’ve
expanded the scope of formatting attributes on the layout element to
capture the entire scope of the “citation” (the cite cluster),
including its prefix and suffix:

This will, for example, permit constructions like
[1,2,5-9], which seems desireable. I don’t see a
downside to this treatment, but this note for information. I’ve
included this in a test to confirm the behavior:

Can roll back the change or modify if someone sees a problem that I’ve
not spotted.