Add an example image to the slope graph documentation

Author: NicholasMamo

docs/.doctrees/environment.pickle

@@ -1,2 +1,2 @@
 <?xml version='1.0' encoding='utf-8'?>
-<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><url><loc>https://nicholasmamo.github.io/multiplex-plot/index.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/genindex.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/py-modindex.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/search.html</loc></url></urlset>
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"><url><loc>https://nicholasmamo.github.io/multiplex-plot/drawable.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/index.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/slope.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/genindex.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/py-modindex.html</loc></url><url><loc>https://nicholasmamo.github.io/multiplex-plot/search.html</loc></url></urlset>

docs/.doctrees/slope.doctree

@@ -190,6 +190,7 @@ <h1>6. Slope Graph<a class="headerlink" href="#slope-graph" title="Permalink to
 <li>Over a time period.</li>
 </ul>
 <p>Slope graphs are not commonly included in visualization packages, but they can be great tools to tell a story.</p>
+<img alt="_images/6-slope.png" class="example inline" src="_images/6-slope.png" />
 <p>To draw a slope graph, create a <a class="reference internal" href="drawable.html#drawable.Drawable" title="drawable.Drawable"><code class="xref py py-class docutils literal notranslate"><span class="pre">Drawable</span></code></a> class and call the <a class="reference internal" href="drawable.html#drawable.Drawable.draw_slope" title="drawable.Drawable.draw_slope"><code class="xref py py-func docutils literal notranslate"><span class="pre">draw_slope()</span></code></a> function:</p>
 <div class="highlight-python notranslate"><div class="highlight"><pre><span></span><span class="kn">import</span> <span class="nn">matplotlib.pyplot</span> <span class="k">as</span> <span class="nn">plt</span>
 <span class="kn">from</span> <span class="nn">multiplex</span> <span class="kn">import</span> <span class="n">drawable</span>

docs/_images/6-slope.png

@@ -6,6 +6,9 @@
 
 Slope graphs are not commonly included in visualization packages, but they can be great tools to tell a story.
 
+.. image:: ../examples/exports/6-slope.png
+   :class: example inline
+
 To draw a slope graph, create a :class:`~drawable.Drawable` class and call the :func:`~drawable.Drawable.draw_slope` function:
 
 .. code-block:: python