Add context to RHS TOC parameter

Author: DrDrij

quantecon_book_theme/layout.html

@@ -88,7 +88,7 @@
 
                 <div class="page__toc">
 
-                    {% if theme_sticky_rhs_toc is defined and theme_sticky_rhs_toc is sameas true %}
+                    {% if theme_sticky_contents is defined and theme_sticky_contents is sameas true %}
                     <div class="inner sticky">
                     {%- else %}
                     <div class="inner">