Filing this in "forms system", because there is no "render system" or "render elements".
The 90% use-case for #prefix and #suffix is surrounding the element in a < div >. With #type 'markup' this doesn't work. You can, of course, wrap the actual #markup in the < div >, but it seems more flexible and also conceptually sensible to separate the actual #markup from something that is just wrapping it.
I'm not aware of any downsides of this, but I'm not that intimate with the render system, so that isn't saying a whole lot.
Not rolling a patch, because I'd like to hear some opinions on this first, but it shouldn't be too hard.
Comments
Comment #1
fran seva CreditAttribution: fran seva commentedComment #2
fran seva CreditAttribution: fran seva commentedComment #3
petar.gnjidic CreditAttribution: petar.gnjidic commentedI'll take this.
Comment #4
petar.gnjidic CreditAttribution: petar.gnjidic commentedComment #5
tim.plunkettComment #6
joelpittetYou can do this:
bartik.theme
bartik/templates/page.html.twig
Produces: