At least when starting a new topic in the Questions category, and maybe in other scenarios, the post preview to the right of where you type your message shows all the instructions as a window that can be closed out of to actually see the preview.
It’s not here now as I write this, not sure that’s the case for every response in every sub-forum, and once you close out of it I don’t see a way to reopen in. And of course if one presses the
<< hide preview button on the bottom right it may never show up at all.
But perhaps if those instructions would appear with every post / can be set as a preference the user preferences - default - so that can also be turned off to not get irritating after learning them, and have a link somewhere in the posting pop up, either in the text formatting bar, or above, to make them show up again after closing them, that might work? And it’s almost there already…
Another thought is: when posting, again at least in questions, the forum is searching for and recommending possible topics that exist that may answer one’s question, so perhaps if it was also coded to pay attention to what looks like code and pop up a reminder with instructions for proper formatting. Not sure how hard that would be, and whether discourse automatically had that questions search built in, or if that was custom made.