Fix language switcher behavior on untranslated pages

This commit fixes the following:
- The language switcher does not appear if a given page does not
  have any translations.
- The current language shown is not presented as an option in the
  language switcher dropdown.

layouts/partials/navbar.html

@@ -36,7 +36,7 @@
 
         {{ end }}
         <li>
-          {{ if and .Site.IsMultiLingual }}
+          {{ if and .Site.IsMultiLingual .IsTranslated }}
             <ul class="sl-nav" aria-label="Language switcher">
               <li>
                 <input type="checkbox" id="languagepicker" aria-label="switch language" hidden />
@@ -46,15 +46,11 @@
 
                 <ul class="dropdown">
 
-                  {{ range $.AllTranslations }}
+                  {{ range $.Translations }}
 
                     <li>
                       <a href="{{ .RelPermalink }}" title="{{ .Language.LanguageName }}"
                         ><span
-                          {{ if eq . $.Site.Language }}
-                            class="active"
-
-                          {{ end }}
                           aria-label="{{ i18n "ariaLanguage" }}{{ .Language.LanguageName }}"
                           >{{ .Language.LanguageName }}</span
                         ></a