Improve readability of the ability histogram section

app.py

@@ -229,7 +229,7 @@ class PersonLayout(ParameterLayout):
 
     def extra(self, df, *args):
         with gr.Row():
-            with gr.Column():
+            with gr.Column('Compare ability'):
                 gr.Markdown(self.text)
 
             with gr.Column(scale=3):

docs/ability.md

@@ -1,7 +1,11 @@
-Probability that Model 1 is preferred to Model 2. The histogram is
+## Probability that Model 1 is preferred to Model 2
+
+Select two models to compare their abilities. The generated histogram
 represents the distribution of the difference in estimated model
-abilities. The dashed vertical line is its median. The shaded region
-demarcates the chosen [highest density
-interval](https://cran.r-project.org/package=HDInterval) (HDI). The
-note in the upper left denotes the smallest HDI that is inclusive of
-$ci
+abilities:
+
+* The dashed vertical line is its median.
+* The shaded region demarcates the chosen [highest density
+  interval](https://cran.r-project.org/package=HDInterval) (HDI).
+* The note in the upper left denotes the smallest HDI that is
+  inclusive of $ci.