Add section shortcode, to render children

assets/_markdown.scss

@@ -137,7 +137,8 @@
     }
 
     dd {
-      margin-inline-start: $padding-16 * 2;
+      margin-inline-start: $padding-16;
+      margin-bottom: $padding-16;
     }
   }
 

exampleSite/content/docs/shortcodes/section/_index.md

@@ -0,0 +1,15 @@
+---
+bookCollapseSection: true
+---
+
+# Section
+
+Section renders pages in section as definition list, using title and description.
+
+## Example
+
+```tpl
+{{</* section */>}}
+```
+
+{{<section>}}

exampleSite/content/docs/shortcodes/section/page1.md

@@ -0,0 +1 @@
+# Page 1

exampleSite/content/docs/shortcodes/section/page2.md

@@ -0,0 +1 @@
+# Page 2

exampleSite/resources/_gen/assets/scss/book.scss_50fc8c04e12a2f59027287995557ceff.json

@@ -1 +1 @@
-{"Target":"book.min.947656565f9248015f7b2c792cb8b8c13ad749e25295c0634f4c7f1d1bde6a0a.css","MediaType":"text/css","Data":{"Integrity":"sha256-lHZWVl+SSAFfeyx5LLi4wTrXSeJSlcBjT0x/HRveago="}}
+{"Target":"book.min.1205ebacf147e31d6bd6f74be1ef8d96f4bb2c4943c68e5a39b4e988a774a2b0.css","MediaType":"text/css","Data":{"Integrity":"sha256-EgXrrPFH4x1r1vdL4e+NlvS7LElDxo5aObTpiKd0orA="}}

layouts/shortcodes/section.html

@@ -0,0 +1,10 @@
+<dl>
+{{ range .Page.Pages }}
+  <dt>
+    <a href="{{ .RelPermalink }}">{{ partial "docs/title" . }}</a>
+  </dt>
+  <dd>
+    {{ default .Summary .Description }}
+  </dd>
+{{ end }}
+</dl>