Or like Milan, wordpad works, you may have to rotate your paper and turn off word wrap.
you can use any text editor, but i prefer to use Notepad++. See link:Notepad++ Home
The "messy" picture you show is actually also the laypout in my file the first time i opened it :-(. So i had to use tabulator to arrange it so it looked nice.
But Notepad++ i prefer also because it remembers all the text files you have had opened, so you dont have to look for them anymore (unless you really edit a lot of text files i guess). See in red below.
Be sure to back up those files or move them elsewhere and point to them with a configuration option (assuming there is one).
It is too easy to loose customized files on Creo release updates if they are buried in the Creo folder structure.