fix yaml front matter (#2617)

futekov · web-flow · commit 1f7f419e5212 · 2021-08-22T14:39:56.000+08:00
The yaml front matter of mixins.md is broken due to a newline at the beginning, this results in a missing docs page on stylus-lang.com
diff --git a/docs/mixins.md b/docs/mixins.md
@@ -1,4 +1,3 @@
-
 ---
 layout: default
 permalink: docs/mixins.html
