Discord supports old and new invite code styles (daattali#1135)

Author: Nico is LOST

_config.yml

@@ -73,7 +73,7 @@ social-network-links:
 #  mastodon: instance.url/@username
 #  ORCID: your ORCID ID
 #  google-scholar: your google scholar
-#  discord: invite/invite_code or users/userid 
+#  discord: "invite_code" or "users/userid" or "invite/invite_code" 
 #  kaggle: yourname
 #  hackerrank: yourname
 

_includes/social-networks-links.html

@@ -301,8 +301,12 @@
 {%- endif -%}
 
 {%- if site.social-network-links.discord -%}
+  {% assign discord_start = site.social-network-links.discord | split: "/" | first -%}
+  {% unless discord_start == 'users' or discord_start == 'invite' -%}
+    {% assign discord_url_prefix = 'invite/' -%}
+  {% endunless -%}
   <li class="list-inline-item">
-    <a href="https://discord.com/{{ site.social-network-links.discord }}" title="Discord">
+    <a href="https://discord.com/{{discord_url_prefix}}{{site.social-network-links.discord}}" title="Discord">
       <span class="fa-stack fa-lg" aria-hidden="true">
         <i class="fas fa-circle fa-stack-2x"></i>
         <i class="fab fa-discord fa-stack-1x fa-inverse"></i>