title: Fill between vertical curves with Julia Plots
body: <p>I am looking for a feature similar to <code>ribbon</code> that would allow me to fill the area between vertical curves <code>x=x(y)</code> using Julia Plots. Right now, using <code>ribbon</code> allows to fill the area between two curves <code>y=y(x)</code>, like in this example:</p>
  <pre><code>using Plots
  y(x) = broadcast(sin, x)
  x = range(0.0, 3.14, length=30)
  plot(x,y(x), ribbon=(zero(x).+0.05, zero(x).+0.1))
  savefig(&quot;ribbon_example.png&quot;)
  </code></pre>
  <p><a href="https://i.stack.imgur.com/p8W6n.png" rel="noreferrer"><img src="https://i.stack.imgur.com/p8W6n.png" alt="example_ribbon" /></a></p>
  <p>I am looking for a way to get similar ribbons in the horizontal. I think a similar keyword argument option does not exist yet (<a href="https://github.com/JuliaPlots/Plots.jl/issues/2702" rel="noreferrer">see this issue</a>), but I was wondering if other options to resolve this problem exist. For other examples, <a href="https://matplotlib.org/api/_as_gen/matplotlib.axes.Axes.fill_betweenx.html" rel="noreferrer">here is the Python matplotlib implementation of what I would need</a>.</p>