The bolded lines you pointed out are previews of the text at that offset, with the quotation marks denoting the text is commented out. For actually editing the text, you want to toy with what's in the "Strings" section at the bottom of the script. Use XSE's text adjuster tool so you won't have to worry about it bleeding out of the box when editing.
If you need to go over the amount of text present, repoint it to free space first, or you'll start overwriting other scripts and things will begin to break in rather mundane yet efficient ways.
