This has come up in a few places, but I’ll use footnotes as an example. Let’s say I have some ReST text that references a footnote:
can be rendered in a single batch [#foot-diffuse]_.
This looks like this when rendered:

There shouldn’t be a space after text when referencing a footnote. This is what I want it to look like:

The problem is that the space between batch and [#foot-diffuse]_ is not optional. Taking it out makes the ReST not valid and the footnote doesn’t get rendered at all. Is there some way to insert a separator between a word and a directive in ReST without it getting rendered as a space in the final output?
I figured it out. Turns out you can escape the space. This works: