Dictionary keys and values incorrectly serialize some strings

[Coleoid]

The ones I found were tilde, tab, and newline by themselves, or newline within a string.

I'm unclear on the correct fix, so I don't have a PR for you, but here's a test set:

[Theory]
[MemberData(nameof(BuggedString_TestCases))]
public void Some_strings_fail_to_roundtrip_as_a_dictionary_key_or_value(string val)
{
    var obj = new Dictionary<string, string> {
        { val, val },
    };

    var result = DoRoundtripFromObjectTo<Dictionary<string, string>>(obj);

    result.Should().Equal(obj);
    //  The failing strings need quoting and don't get them.
}

public static IEnumerable<Object[]> BuggedString_TestCases
{
    //  All these values correctly round-trip as simple strings.
    get
    {
        //  These values fail to round-trip correctly as key or value in a dictionary.
        yield return new Object[] { "~" };
        yield return new Object[] { "\n" };
        yield return new Object[] { "\t" };
        yield return new Object[] { "x\nx" };

        //  These values round-trip correctly despite similarity to failing cases.
        yield return new Object[] { "x~x" };
        yield return new Object[] { "x\tx" };
        yield return new Object[] { " ~ " };
        yield return new Object[] { " \n " };
        yield return new Object[] { " \t " };
    }
}

[aaubry]

Thanks for reporting this. I'll need some time to look into this in order to fix it.