Add support for targetLinkLanguage field

Author: JamieC24

templates/components/styles/global_nav.html.twig

@@ -1,6 +1,7 @@
 <nav id="global-nav" aria-label="Main">
     <div class="global-nav__inner l-center">
-        <a class="logo-link" href="{% block homepage_link %}/{% endblock %}" hreflang="{% block homepage_hreflang %}en{% endblock %}">
+        {% set siteLang %} {% block homepage_hreflang %}en{% endblock %} {% endset %}
+        <a class="logo-link" href="{% block homepage_link %}/{% endblock %}" hreflang="{{ siteLang }}">
             <span class="logo">
                 <img src="{{ absolute_url(asset('w3c/w3c-no-bars.svg', 'logos')) }}" alt="{{ 'header.logo_alt'|trans({}, 'w3c_website_templates_bundle') }}" role="img"/>
             </span>
@@ -11,8 +12,9 @@
         <ul data-component="nav-double-intro">
             {%~ for navItem in navigation %}
                 <li class="top-nav-item has-children">
+                    {% set langDiff = siteLang is same as navItem.targetLinkLanguage ? false : true %}
                     {% if navItem.language is defined %}{{ navItem.language }}{% endif %}
-                    <a href="{{ navItem.titleLink }}" class="nav-link">{{ navItem.title }}</a>
+                    <a href="{{ navItem.titleLink }}" class="nav-link"{% if langDiff %}hreflang="{{ navItem.targetLinkLanguage }}"{% endif %}>{{ navItem.title }}</a>
                     <div class="nav__submenu" data-nav="submenu" style="display: none;">
                         <div class="l-center">
                             <div class="nav__submenu__intro">
@@ -29,8 +31,9 @@
                             {% if navItem.children is defined and navItem.children|length > 0 -%}
                                 <ul>
                                     {%~ for child in navItem.children %}
+                                        {% set childLangDiff = siteLang is same as child.targetLinkLanguage ? false : true %}
                                         <li{{ child.startNewColumn is defined and child.startNewColumn ? ' class="break-after"' : '' }}>{# -#}
-                                            <a href="{{ child.url }}">{{ child.title }}</a>{# -#}
+                                            <a href="{{ child.url }}{% if childLangDiff %}hreflang="{{ child.targetLinkLanguage }}"{% endif %}">{{ child.title }}</a>{# -#}
                                         </li>
                                     {%~ endfor %}
                                 </ul>