XWIKI-14532: Nested definition lists don't appear nested

- Adding margin for nested description lists, while preserving the Bootstrap's style for main list

xwiki-platform-core/xwiki-platform-flamingo/xwiki-platform-flamingo-skin/xwiki-platform-flamingo-skin-resources/src/main/resources/flamingo/less/type.less

@@ -65,4 +65,11 @@ ul.xlist li.create a {
 tt.wikimodel-verbatim, span.wikimodel-verbatim {
   font-family: sans-serif;
   white-space: pre-wrap;
-}
\ No newline at end of file
+}
+
+// Description Lists ======================================================
+
+dl dd dl {
+  margin-left: @grid-gutter-width;
+  margin-bottom: 0;
+}