Merge commit '9b0050e9aabe4be65c78ccf292a348f309d50ccd' as 'docs'

```
git subtree add --prefix=docs/ https://github.com/gohugoio/hugoDocs.git master --squash
```

Closes #11925

docs/content/en/functions/_index.md

@@ -0,0 +1,17 @@
+---
+title: Functions
+linkTitle: Overview
+description: A list of Hugo template functions including examples.
+categories: []
+keywords: []
+menu:
+  docs:
+    identifier: functions-overview
+    parent: functions
+    weight: 10
+weight: 10
+showSectionMenu: true
+aliases: [/layout/functions/,/templates/functions]
+---
+
+Use these functions within your templates and archetypes.