Incorrect parsing of the contents of triple-quoted strings

[jfmengels]

When encountering double backslashes (\\) in triple quotes, the order of characters is wrong.

module A exposing (..)
_ = """\\{"""
_ = """\\{\\}"""
_ = """\\}\\{"""
_ = """\\[\\]"""
_ = """\\(\\)"""
_ = """\\a\\b"""
_ = """\\a-blablabla-\\b"""

For instance \\{\\} becomes \\}\\{

To play with those interactively, I made an Ellie. It's in Elm code, so there is a lot of escaping unfortunately https://ellie-app.com/bbmqddVmJzka1 (see line ~65)