Most blogging platforms support this by default: Using <kbd>; tags for highlighting keyboard shortcuts, such as <kbd>ctrl</kbd>+<kbd>c</kbd>. But doing this manually is tedious or even infeasible for lengthy posts with a large number of keys.
I have written a blog post about how to add tags automatically with a single regex-based replace operation.
https://tkainrad.dev/posts/automatically-add-kbd-tags-with-a-single-regex/