Symbols: Add a "Copy Content Input" button

When building dynamic Symbols with many Content Inputs, I find that I often have a need to copy a previous Content Input and just change the name. It'd be really nice if I didn't have to go into the JSON Editor to do that and could just click a button (even if it's in the More Options section) to copy it and automatically add an incremented value to the end of it (i.e. FAQ1, FAQ2, etc.)