fix: Remove extra closing code block from dynamic variables documentation

Author: codebuster22

fern/assistants/dynamic-variables.mdx

@@ -116,7 +116,6 @@ Outputs: `Monday, January 01, 2024, 03:45 PM`
 | `%H:%M`        | 15:45         | 24-hour time        |
 | `%A`           | Monday        | Day of week         |
 | `%b %d, %Y`    | Jan 01, 2024  | Abbrev. Month Day   |
-```
 
 ## Using dynamic variables in the dashboard
 
@@ -131,4 +130,3 @@ When you start a call, you must provide a value for each variable (like `name`)
 <Note>
 Always use double curly braces (`{{variableName}}`) to reference dynamic variables in your prompts and messages.
 </Note>
-</rewritten_file>