Inline code syntax highlighting in GitHub markdown?
Solution 1:
GitHub comments, wikis, README.md etc. use GFM, essentially CommonMark with some extensions. There it's not possible.
However, GitHub Pages uses Jekyll and by extension kramdown where you can use:
`x = 4`{:.ruby}
P.S. If you happen to use pandoc, the syntax is:
`x = 4`{.ruby}