I like to use the markdown-mode for READMEs.
And I would like to use the markdown-mode as a minor-mode for comments in other major-modes like sh-mode. Is this possible somehow?
markdown-minor-mode would be nice, yes. I currently have some ad-hoc code to highlight comments assuming markdown syntax for my typer-mode. It only supports a limited subset of markdown and only performs highlighting, but it shouldn't be difficult to extract it into its own
markdown-minor-mode (probably easier than to try and adapt the code from
markdown-mode major mode).