[livemdpreview] expand parameter descriptions

Author: jcb91

src/jupyter_contrib_nbextensions/nbextensions/livemdpreview/livemdpreview.yml

@@ -8,13 +8,16 @@ Parameters:
 
 - name: livemdpreview.show_side_by_side
   description: |
-    Show the input & output of markdown cells side-by-side while editing
+    Show the input & output of markdown cells side-by-side while editing them.
+    Otherwise, the output appears immediately below the input while editing
   input_type: checkbox
   default: false
 
 - name: livemdpreview.timeout
   description: |
-    Minimum time between edits to the markdown source & updating its output
+    Minimum time in ms between editing the markdown source & its output being
+    updated. This throttles the rate at which consecutive renderings will take
+    place.
   input_type: number
   default: 500
   min: 10