Remove blank lines from Nunjucks code in Examples

lib/file-helper.js

@@ -37,10 +37,15 @@ exports.getNunjucksCode = path => {
   // Omit any `{% extends "foo.njk" %}` nunjucks code, because we extend
   // templates that only exist within the Design System – it's not useful to
   // include this in the code we expect others to copy.
-  let content = parsedFile.content.replace(
+  let content = parsedFile.content
+  .replace(
     /{%\s*extends\s*\S*\s*%}\s+/,
     ''
   )
+  .replace(
+    /^\s*[\r\n]/gm,
+    ''
+  )
 
   return content
 }