I am a big fan of typography but I have to draw the line at ligatures in code samples. It's just not appropriate for type that actually has a compelling reason to be monospaced =)
// application.css:529
body {
-webkit-font-feature-settings: "kern", "liga", "pnum";
-ms-font-feature-settings: "kern", "liga", "pnum";
font-feature-settings: "kern", "liga", "pnum";
// ...
}