Missing background for language tabs

[mpkorstanje]

Some docs pages are polyglot and have versions for Java, JavaScript, Ruby, ect. Each is displayed in its own tab. However the current layout lacks the typical hints that these are in fact tabs. The icons alone visually disappear into the background.

For example see:

https://cucumber.io/docs/guides/10-minute-tutorial/

@declark can you add some hints to make it more obvious these are tabs?

Browser: Firefox 71.0