Fix multi-line strings are not allowed for key

In spec https://github.com/toml-lang/toml#keys

Quoted keys are clarified as

> he exact same rules as either basic strings or literal strings

TOML clearly distinguishes basic string and multi-line basic string
(literal string is also).

https://github.com/toml-lang/toml#string

So table key and quoted key should not allow multi-line basic string
and multi-line literal string.

ABNF definition also describes that.

https://github.com/toml-lang/toml/blob/master/toml.abnf

```
string = ml-basic-string / basic-string / ml-literal-string / literal-string

quoted-key = basic-string / literal-string
```

`string` contains `ml-*` but `quoted-key` doesn't.

0 files changed, 0 insertions, 0 deletions