URL Encode Title and Page URL in Social Share Links

The links to the various social networks include data from the post
(title and url) which can contain URL special characters.  Pass each of
the generated URLs through Liquid's `url_encode` filter to build HTML
complaint URLs.

_includes/social-share.html

@@ -3,11 +3,11 @@
     <h4 class="page__share-title">{{ site.data.ui-text[site.locale].share_on_label | default: "Share on" }}</h4>
   {% endif %}
 
-  <a href="https://twitter.com/intent/tweet?{% if site.twitter.username %}via={{ site.twitter.username }}&{% endif %}text={{ page.title }} {{ page.url | absolute_url }}" class="btn btn--twitter" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Twitter"><i class="fa fa-fw fa-twitter" aria-hidden="true"></i><span> Twitter</span></a>
+  <a href="https://twitter.com/intent/tweet?{% if site.twitter.username %}via={{ site.twitter.username | url_encode }}&{% endif %}text={{ page.title | url_encode }}%20{{ page.url | absolute_url | url_encode }}" class="btn btn--twitter" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Twitter"><i class="fa fa-fw fa-twitter" aria-hidden="true"></i><span> Twitter</span></a>
 
-  <a href="https://www.facebook.com/sharer/sharer.php?u={{ page.url | absolute_url }}" class="btn btn--facebook" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Facebook"><i class="fa fa-fw fa-facebook" aria-hidden="true"></i><span> Facebook</span></a>
+  <a href="https://www.facebook.com/sharer/sharer.php?u={{ page.url | absolute_url | url_encode }}" class="btn btn--facebook" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Facebook"><i class="fa fa-fw fa-facebook" aria-hidden="true"></i><span> Facebook</span></a>
 
-  <a href="https://plus.google.com/share?url={{ page.url | absolute_url }}" class="btn btn--google-plus" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Google Plus"><i class="fa fa-fw fa-google-plus" aria-hidden="true"></i><span> Google+</span></a>
+  <a href="https://plus.google.com/share?url={{ page.url | absolute_url | url_encode }}" class="btn btn--google-plus" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} Google Plus"><i class="fa fa-fw fa-google-plus" aria-hidden="true"></i><span> Google+</span></a>
 
-  <a href="https://www.linkedin.com/shareArticle?mini=true&url={{ page.url | absolute_url }}" class="btn btn--linkedin" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} LinkedIn"><i class="fa fa-fw fa-linkedin" aria-hidden="true"></i><span> LinkedIn</span></a>
+  <a href="https://www.linkedin.com/shareArticle?mini=true&url={{ page.url | absolute_url | url_encode }}" class="btn btn--linkedin" title="{{ site.data.ui-text[site.locale].share_on_label | default: 'Share on' }} LinkedIn"><i class="fa fa-fw fa-linkedin" aria-hidden="true"></i><span> LinkedIn</span></a>
 </section>