I want to include sub-headings in an answer I am writing. I think I have done it before, and I thought it was just a matter of clicking the heading button again.
When I highlight my heading and click the heading button in the toolbar, a line is inserted under the selected line, and this line is filled with dashes "---". If I click heading button again, the dashes are changed to equals signs "===", but the text in the preview area still looks like a full size heading. Clicking the heading button again puts it back to normal with no heading.
My question here is "How do I apply a sub-heading in a Stack Exchange post?" However, is there any place on Stack Exchange that documents the features and what text in the text area represents those features? It would be very useful if a good answer included a link to such documentation. If I knew that "%%% My Subheading %%%" did what I wanted, I could just type it in directly.
Some things I have tried
I have Googled this, which results in a lot of UX/HTML/TeX SE questions about headings with those technologies instead of doing it within a SE question/answer.
I have used SE's search and that is not doing it for me either.
I skimmed through some of the questions in the markdown tag, but that was not helpful.
I would just use bold text instead of a sub-heading, but I think someone criticized me for that one time in the past, if I recall correctly.