Lint render-symbolic.rb with rubocop --fix

Whitespace removal Put spaces after commas File.exists? is deprecated, use File.exist? Use tabs correctly Alignment with code Put spaces after # and commas

So with the release of Ruby 3.0, and me building and installing Ruby 3.0 to my system, I decided to check over the Ruby file and lint it. There was a lot of whitespaces and tabs were used sort of weirdly.

Rubocop was able to easily fix all of these and they weren't a big issue. The long diff's are just whitespace/tab fixes most likely, or adding commas where necessary.