Document downcase

_filters/downcase.md

@@ -0,0 +1,11 @@
+---
+title: downcase
+---
+
+This filter makes the entire input string the lower case version of each character within.
+
+| Code                                                   | Output           |
+|-------------------------------------------------------:|:-----------------|
+| {% raw %}`{{ "Peter Parker" | downcase }}`{% endraw %} | `"peter parker"` |
+
+It doesn't modify strings which are already entirely lowercase. It works with anything that has a `#to_s` method.