title: Trying to make a paneled spaghetti chart with highlighted line
body: <p>I'm trying to make a graph like the one found here at the very bottom: <a href="https://www.data-to-viz.com/caveat/spaghetti.html" rel="nofollow noreferrer">https://www.data-to-viz.com/caveat/spaghetti.html</a></p>
  
  <p>unfortunately I have a character variable instead of a numeric one for the x axis (I have four years by months), and I don't get the grey lines as in that graph per panel. Does anyone know how else to obtain that graph? </p>