Default TomlEncoder does not escape backslashes correctly

[Poofjunior]

This is mainly an issue storing windows file paths.

In a nutshell, a config containing this data:

# config.toml
[specs]
my_path = "C:\\Program Files\\Euresys\\Memento\\bin\\x86_64\\memento.exe" 

can be loaded with:

cfg = toml.load("config.toml")

and then saved with:

with open("new_config.toml", 'w') as f:
    f.write(toml.dumps(cfg))

But the result will remove the first two double backslashes for some characters that can be incorrectly parsed as valid.

# new_config.toml
[specs]
my_path = "C:\Program Files\Euresys\Memento\bin\x86_64\\memento.exe"  

It looks like the double-backslash is not recognized when the next character forms a valid unicode shorthand?