Make button shortcode use portable links

exampleSite/content.en/_index.md

@@ -11,7 +11,7 @@ layout: landing
 
 {{< badge style="info" title="Badge" value="Value" >}} {{< badge style="default" title="Badge" value="Value" >}}
 
-{{<button relref="/docs/example">}}Button{{</button>}}
+{{<button href="/docs/example">}}Button{{</button>}}
 
 </div>
 

exampleSite/content.en/docs/shortcodes/buttons.md

@@ -9,5 +9,5 @@ Buttons are styled links that can lead to local page or external link.
 {{</* button href="https://github.com/alex-shpak/hugo-book" */>}}Contribute{{</* /button */>}}
 ```
 
-{{<button relref="/">}}Get Home{{</button>}}
+{{<button href="/">}}Get Home{{</button>}}
 {{<button href="https://github.com/alex-shpak/hugo-book">}}Contribute{{</button>}}

layouts/_shortcodes/button.html

@@ -1,12 +1,5 @@
-{{- $ref := "" }}
-{{- $target := "" -}}
-{{- with .Get "href" -}}
-  {{- $ref = . -}}
-  {{- $target = "_blank" -}}
-{{- end -}}
-{{- with .Get "relref" -}}
-  {{- $ref = relref $ . -}}
-{{- end -}}
-<a {{ with $ref }} href="{{.}}" {{ end }} {{ with $target }} target="{{.}}" rel="noopener" {{ end }} class="book-btn{{ with .Get "class" }} {{ . }}{{ end }}">
+{{ $href := partial "docs/links/portable-link" (dict "Page" .Page "Destination" (.Get "href")) -}}
+{{ $isRemote := (urls.Parse $href).Scheme}}
+<a {{ with $href }}href="{{ $href }}"{{ end }} {{ with $isRemote }}target="_blank" rel="noopener"{{ end }} class="book-btn{{ with .Get "class" }} {{ . }}{{ end }}">
   {{- .InnerDeindent -}}
 </a>