Inline Table's commas

[kenodegard]

In accordance with the grammar

https://github.com/toml-lang/toml/blob/bb47759841ac368d86eb7a459bd7eea7162b9a80/toml.abnf#L213-L221

leading, trailing, and duplicate commas are not allowed.

In other words the following cases should not be allowed (but currently are possible):

1. No comma:

   a = { b = 12  c= 'hello' }
   

2. Leading comma:

   a = { , b = 12 }
   

3. Duplicate comma:

   a = { b = 12 ,,,,,, c='hello' }
   

4. Trailing comma:

   a = { b = 12 , }
   

I have also addressed this with a fix dependent upon #15.

[frostming]

This was fixed