Add support for neovim async

[mitermayer]

This issue will be used to track adding support for neovim async, at this moment neovim async is release under a feature flag, however as #96 there are still some bugs that needs to be fixed before the dark feature flag can be removed.

Users that want to experiment with the neovim async and/or want to help tackle this issue can enable it in the meantime by:

   g:prettier#nvim_unstable_async=1

While this issue is open the neovim behaviour will keep working as before by defaulting to sync

• fix bugs reported on Neovim unstable async formatting bugs #96
• testing on neovim 0.2.0
• removing darkfeature flag

[FabioAntunes]

I would gladly help in anything you guys need, except scripting. Let me know if you need any help on testing.

[mitermayer]

This issue is been tackled on the release 1.x branch and will be closed once vim-prettier 1.0 is released.

[mitermayer]

This feature is now available on 1.x release branch

[mitermayer]

@FabioAntunes if you have some time could you try out the 1.x release branch ?

[FabioAntunes]

@mitermayer Sorry for the super late response I have been using ALE lately, I will give it a try if you need

[mitermayer]

@FabioAntunes,

Not a problem! If you have some time please feel to try our 1.x branch as it have neovim support for async already working in there

[mitermayer]

I am closing this issue as this is now resolved on 1.x branch