fix: dont apply relURL function to remote urls in render-link template

exampleSite/content/contact.md

@@ -3,5 +3,6 @@ title: "Get in touch"
 ---
 
 - **E-Mail:** <!-- spellchecker-disable -->mail [ett] example.com<!-- spellchecker-enable -->
+- **Mailto:** [contact@example.com](mailto:contact@example.com)
 - **Matrix:** @john:example.com
 - **XMPP:** john@example.com

layouts/_default/_markup/render-link.html

@@ -1,2 +1,7 @@
-{{ $raw := or (hasPrefix .Text "<img") (hasPrefix .Text "<figure") }}
-<a class="gblog-post__link{{ if $raw }}--raw{{ end }}" href="{{ .Destination | safeURL | relURL }}"{{ with .Title }} title="{{ . }}"{{ end }}>{{ .Text | safeHTML }}</a>
+{{- $raw := or (hasPrefix .Text "<img") (hasPrefix .Text "<figure") -}}
+{{- $isRemote:= or (in .Destination ":") ( hasPrefix .Destination "//") -}}
+{{- $destination := .Destination | safeURL -}}
+{{- if not $isRemote -}}
+    {{- $destination = $destination | relURL -}}
+{{- end -}}
+<a class="gblog-post__link{{ if $raw }}--raw{{ end }}" href="{{ $destination }}"{{ with .Title }} title="{{ . }}"{{ end }}>{{ .Text | safeHTML }}</a>