feat: add option to show superuser social links in header (#2010)

To use, add label and display options to superuser's `social` links:

```
social:
- icon: twitter
  icon_pack: fab
  link: https://twitter.com/<USERNAME>
  label: Follow me on Twitter
  display:
    header: true
```

wowchemy/layouts/partials/functions/get_social_link.html

@@ -0,0 +1,37 @@
+{{/* Function to return a linked social icon as a map from an iteration of an author's `social` data. */}}
+
+{{ $scr := newScratch }}
+
+{{/* Get icon name. */}}
+{{ $scr.SetInMap "social_link" "icon" .icon }}
+
+{{/* Get icon pack (default to Font Awesome's Solid pack). */}}
+{{ $pack := or .icon_pack "fas" }}
+{{ $scr.SetInMap "social_link" "icon_pack" $pack }}
+
+{{/* Derive Font Awesome class name prefix. */}}
+{{ $pack_prefix := $pack }}
+{{ if in (slice "fab" "fas" "far" "fal") $pack }}
+  {{ $pack_prefix = "fa" }}
+{{ end }}
+{{ $scr.SetInMap "social_link" "pack_prefix" $pack_prefix }}
+
+{{/* Get tooltip label (default to none). */}}
+{{ $scr.SetInMap "social_link" "tooltip" (.label | default "") }}
+
+{{/* Get screen reader label (default to icon name). */}}
+{{ $scr.SetInMap "social_link" "aria_label" (.label | default .icon) }}
+
+{{/* Get external link or relative internal link. */}}
+{{ $link := .link }}
+{{ $target := "" }}
+{{ $scheme := (urls.Parse $link).Scheme }}
+{{ if not $scheme }}
+  {{ $link = .link | relLangURL }}
+{{ else if in (slice "http" "https") $scheme }}
+  {{ $target = "target=\"_blank\" rel=\"noopener\"" }}
+{{ end }}
+{{ $scr.SetInMap "social_link" "link" $link }}
+{{ $scr.SetInMap "social_link" "target" $target }}
+
+{{ return $scr.Get "social_link" }}

wowchemy/layouts/partials/navbar.html

@@ -139,6 +139,19 @@
     </div><!-- /.navbar-collapse -->
 
     <ul class="nav-icons navbar-nav flex-row ml-auto d-flex pl-md-2">
+
+      {{/* Display any social links that the superuser chose to display in the header. */}}
+      {{ range where (where (where site.Pages "Section" "authors") ".Params.superuser" true) ".Params.social" "!=" nil }}
+        {{ range where .Params.social ".display.header" true }}
+          {{ $social_link := partial "functions/get_social_link" . }}
+          <li class="nav-item d-none d-lg-inline-flex">
+            <a class="nav-link" href="{{ $social_link.link | safeURL }}"{{ with $social_link.tooltip }} data-toggle="tooltip" data-placement="bottom" title="{{.}}"{{ end }} {{ $social_link.target | safeHTMLAttr }} aria-label="{{ $social_link.aria_label }}">
+              <i class="{{ $social_link.icon_pack }} {{ $social_link.pack_prefix }}-{{ $social_link.icon }}" aria-hidden="true"></i>
+            </a>
+          </li>
+        {{ end }}
+      {{ end }}
+
       {{ $show_search := site.Params.main_menu.show_search | default true }}
       {{ if and site.Params.search.engine $show_search }}
       <li class="nav-item">