title: How to Trim a String in Swift based on a character
body: <p>I would like to trim this string, so that I can extract the filename, which is always preceded by an "_" (underscore).  What is the best way to do this?</p>
  
  <p><a href="https://s3.amazonaws.com/brewerydbapi/beer/RXI2cT/upload_FfAPfl-icon.png" rel="noreferrer">https://s3.amazonaws.com/brewerydbapi/beer/RXI2cT/upload_FfAPfl-icon.png</a></p>
  
  <p>I would like the result to be FfAPfl-icon.png</p>