Fix lighthouse remarks: icon sizes, noopener

layouts/partials/docs/menu-filetree.html

@@ -31,7 +31,7 @@
   {{ if .Page.Params.bookCollapseSection }}
     <input type="checkbox" id="section-{{ md5 .Page }}" class="toggle" {{ if or $current $ancestor }}checked{{ end }} />
     <label for="section-{{ md5 .Page }}" class="flex justify-between">
-      <a {{ if .Page.Content }}href="{{ .Page.Permalink }}"{{ end }} class="{{ if $current }}active{{ end }}">
+      <a {{ if .Page.Content }}href="{{ .Page.Permalink }}"{{ else }}role="button"{{ end }} class="{{ if $current }}active{{ end }}">
         {{- partial "docs/title" .Page -}}
       </a>
     </label>

layouts/shortcodes/button.html

@@ -7,6 +7,6 @@
 {{ with .Get "relref" }}
   {{ $ref = relref $ . }}
 {{ end }}
-<a {{ with $ref }} href="{{.}}" {{ end }} {{ with $target }} target="{{.}}" {{ end }} class="book-btn{{ with .Get "class" }} {{ . }}{{ end }}">
+<a {{ with $ref }} href="{{.}}" {{ end }} {{ with $target }} target="{{.}}" rel="noopener" {{ end }} class="book-btn{{ with .Get "class" }} {{ . }}{{ end }}">
   {{ $.Inner | markdownify }}
 </a>