The accepted answer only solves for doc strings and in cases where people are willing to adjust the message in the triple quoted text. I currently have test cases where I have to paste in a complete message and I use triple double quotes. In this case, I am not going to adjust my multiline test message and sadly, notepad++ will only fold the first paragraph.
testcases.append("""Lorem Ipsum is simply dummy text of
the printing and typesetting industry. Lorem Ipsum has been
the industry's standard dummy text ever since the 1500s, when
an unknown printer took a galley of type and scrambled it to make
a type specimen book.
It has survived not only five centuries, but also the leap into
electronic typesetting, remaining essentially unchanged. It was
popularized...""")