Add TOC back

themes/sigpipe/layouts/partials/sidebar.html

+{{ if .IsPage }}
+<h4>TOC</h4>
+{{.TableOfContents}}
+{{ end }}
+
 {{ range $section, $taxonomy := .Site.Sections.ByTitle }}
     <h4>{{ $taxonomy.Params.Title | default $taxonomy.Section }}</h4>
     <ul>