content: Replace calls to the code shortcode with fenced code blocks

content/en/methods/shortcode/Parent.md

@@ -14,19 +14,19 @@ This is useful for inheritance of common shortcode arguments from the root.
 
 In this contrived example, the "greeting" shortcode is the parent, and the "now" shortcode is child.
 
-{{< code file=content/welcome.md lang=text >}}
+```text {file="content/welcome.md"}
 {{</* greeting dateFormat="Jan 2, 2006" */>}}
 Welcome. Today is {{</* now */>}}.
 {{</* /greeting */>}}
-{{< /code >}}
+```
 
-{{< code file=layouts/shortcodes/greeting.html >}}
+```go-html-template {file="layouts/shortcodes/greeting.html"}
 <div class="greeting">
   {{ .Inner | strings.TrimSpace | .Page.RenderString }}
 </div>
-{{< /code >}}
+```
 
-{{< code file=layouts/shortcodes/now.html >}}
+```go-html-template {file="layouts/shortcodes/now.html"}
 {{- $dateFormat := "January 2, 2006 15:04:05" }}
 
 {{- with .Params }}
@@ -42,7 +42,7 @@ Welcome. Today is {{</* now */>}}.
 {{- end }}
 
 {{- now | time.Format $dateFormat -}}
-{{< /code >}}
+```
 
 The "now" shortcode formats the current time using: