From my personal experience, it's useful if the editor has at least some basic support for this kind of blocks, e. g. enter key opens a line with same indent level etc. And editor scripting also helps, then you can write a script toreport the indent level on demand. Of course, many screen readers can report the number of spaces/tabs (e. g. the raw value), but you usually want only the level with respect to the current codebase and most likely only sometimes e. g. not on every line movement, you can infer the blocks sometimes from context and recheck only if needed/things go wrong.
I'm not the original author, but a blind coder nonetheless, so i think it's worth responding anyway. Sublime is an accessibility disaster, unfortunately, Emacs can be used, but it's much more productive with EmacsSpeak or Speechd-el. Vim would likely need something similar, because the advanced cursor movement commands have no screen reader feedback by default.
The HN ui is quite okay, but some semantic comment nesting (like disqus comments, perhaps?) would help. Might be some filtering for new comments since last visit.