title: Replace characters inside a RegEx match
body: <p>I want to match certain lines inside any text and inside that match, I want to replace a certain character as often, as it occurs.
  Sample Text:</p>
  
  <blockquote>
    <p>Any text and "much" "more" of it. Don't replace quotes here<br>
    <strong>CatchThis(  no quotes here, "any more text"   ,  "and so on and so forth...")</strong><br>
    <strong>catchthat("some other text"   , "or less")</strong><br>
    some text in "between"<br>
    <strong>CatchAnything ( "even more"  , "and more", no quotes there, "wall of text")</strong><br>
    more ("text"""") and quotes after...</p>
  </blockquote>
  
  <p>Now I want to replace every quote inside the round brackets with, lets say, a hash sign.
  Desired outcome:</p>
  
  <blockquote>
    <p>Any text and "much" "more" of it. Don't replace quotes here<br>
    <strong>CatchThis(  no quotes here, #any more text#   ,  #and so on and so forth...#)</strong><br>
    <strong>catchthat(#some other text#   , #or less#)</strong><br>
    some text in "between"<br>
    <strong>CatchAnything ( #even more#  , #and more#, no quotes there, #wall of text# )</strong><br>
    more ("text"""") and quotes after...</p>
  </blockquote>
  
  <p>Matching the lines is easy. Here's my pattern for that:</p>
  
  <pre><code>(?i)Catch(?:This|That|Anything)[ \t]*\(.+\)
  </code></pre>
  
  <p>Unfortunately, I have no idea how to match every quote and replace it...</p>