Could anyone advise what the preferred/recommended license is for the documentation associated with fonts licensed under the OFL?
If it’s integrated into the project - such as .md files in the same project package/repo, and expected to be distributed alongside everything else - then they reasonably fall under the same OFL as the rest of the project. There’s no specific recommendation other than that, however keep in mind that if you put a doc with a more restrictive license in the repo it can cause problems.
I was hung up on the use of “Font Software” in the OFL. However “Font Software” is defined so that it " … may include source files, build scripts and documentation."
… problem (of my own making) solved!