Remove the 'slug' attribute from open-a-pr

tengqm · tengqm · commit 96b76320c716 · 2020-07-21T18:55:59.000+08:00
The slug is causing problems for tracking missing links. Other than
that, I'm not seeing any advantage of using it.
diff --git a/content/en/docs/contribute/new-content/open-a-pr.md b/content/en/docs/contribute/new-content/open-a-pr.md
@@ -1,6 +1,5 @@
 ---
 title: Opening a pull request
-slug: new-content
 content_type: concept
 weight: 10
 card:
