Add return type to functions

content/en/functions/encoding/Base64Decode.md

@@ -0,0 +1,45 @@
+---
+title: encoding.Base64Decode
+linkTitle: base64Decode
+description: Returns the base64 decoding of the given content.
+categories: [functions]
+keywords: []
+menu:
+  docs:
+    parent: functions
+function:
+  aliases: [base64Decode]
+  returnType: string
+  signatures: [encoding.Base64Decode INPUT]
+signatures:
+  - 
+  - base64Decode INPUT
+aliases: [/functions/base64Decode]
+---
+
+```go-html-template
+{{ "SHVnbw==" | base64Decode }} → "Hugo"
+```
+
+Use the `base64Decode` function to decode responses from APIs. For example, the result of this call to GitHub's API contains the base64-encoded representation of the repository's README file:
+
+```text
+https://api.github.com/repos/gohugoio/hugo/readme
+```
+
+To retrieve and render the content:
+
+```go-html-template
+{{ $u := "https://api.github.com/repos/gohugoio/hugo/readme" }}
+{{ with resources.GetRemote $u }}
+  {{ with .Err }}
+    {{ errorf "%s" . }}
+  {{ else }}
+    {{ with . | transform.Unmarshal }}
+      {{ .content | base64Decode | markdownify }}
+    {{ end }}
+  {{ end }}
+{{ else }}
+  {{ errorf "Unable to get remote resource %q" $u }}
+{{ end }}
+```