title: Adding new characters to beginning and end of each line in textbox
body: <p>I have a textbox with multiline enabled, and want to add a string at the beginning and end of
  each line, so every line would be changed to </p>
  
  <pre><code>a + line + b
  </code></pre>
  
  <p>Now I know it has to do with a foreach loop, but don't know how to write it out.</p>