title: How to make the searchfiles method case-insensitive?
body: <p>I am writing to you because i have some issues with my function that search files in a folder by checking if the key word is in, the problem is that the research is case-sensitive.
  Here is the code i am trying to make case insensitive:</p>
  
  <pre><code>Folder.searchFiles("fullText contains  \'\"" + searchField + "\"\'" )
  
  </code></pre>
  
  <p>I have tried to put REGEX in but it does not recognize REGEX, i am a bit new to google app script  and it would be very kind if someone could help me with this problem, i have tried to find an answer in forums but it seems that there is no similar cases, thank you
  Best regards</p>