fix(table of content): avoid breaks inside of list items

assets/css/base.scss

@@ -181,6 +181,7 @@ th {
   column-gap: var(--l-gap);
   column-width: var(--auto-grid-min-size);
 }
+@import './structures/table-of-content';
 
 .small-left-grid {
   display: grid;

assets/css/structures/_table-of-content.scss

@@ -0,0 +1,3 @@
+.toc__list-item {
+  page-break-inside: avoid;
+}