Support spelling_language property

[gustaphe]

I implemented the discussion in editorconfig/editorconfig#315 . Perhaps this is the wrong way around - it should be put in the standard first. But I don't know how to edit the standard, I know how to edit the implementation.

I'm currently running off my own fork, but in case the standard is updated at least this practical implementation is ready.

[xuhdev]

You are right, it need to be added to the spec first: spec.editorconfig.org. The plugin is a implementation of the spec for Vim.

[cxw42]

Draft specification change using spell_language (based on my reading of the thread): editorconfig/specification#41

[gustaphe]

I don't know how the tests work, but there's a spelling_language in the specification now so here's the implementation.

[cxw42]

LGTM! I am just requesting one change. Thanks for this PR!

[gustaphe]

Sure, fixed this.

Just to mention, the specification is a bit vague on which territory codes are actually included, the ISO lists all of ^[a-z]\{2}\(-[A-Z0-9]\{2,3}\)\?$, but I'm limiting it to ^[a-z]\{2}\(-[A-Z]\{2}\)\?$ because it's the only ones that can be simply converted to vim format. And I've never seen the three letter or digit codes used. If that is ever required, somebody should probably build a lookup table for this.

[cxw42]

Thanks! As for two- vs. three-letter codes, I intended TT in

The format is ss or ss-TT

to be exactly two characters, but your point is well made --- TT could be read as a variable. I have opened editorconfig/specification#48 to fix that. Thank you for reporting the spec issue!

[cxw42]

@gustaphe Spec fix open at editorconfig/specification#54

[gustaphe]

Just checking, is there anything blocking this merge?

[cxw42]

@gustaphe Apologies for the long delay! I have squashed and force-pushed your branch. There are no content changes:

$ git diff --exit-code ec5a000 ca33e23 && echo SAME
SAME

[cxw42]

Style nit: I prefer '\v...' regexes so not as much has to be escaped. However, that is not at all a blocker!

[cxw42]

Sorry for the confusion --- I use Bitbucket at work and got mixed up on the PR UI for a moment. Should merge as soon as Appveyor finishes.

After rebase, also no content changes (the only differences shown in the range diff are in context lines)

$ g range-diff ca33e23^..ca33e23 HEAD^..HEAD
1:  ca33e23 ! 1:  f3d5760 Support spelling_language property
    @@ README.md: The EditorConfig Vim plugin supports the following EditorConfig [prop
      ## Selected Options
     
      ## plugin/editorconfig.vim ##
    -@@ plugin/editorconfig.vim: function! s:ApplyConfig(config) abort " Set the buffer options {{{1
    +@@ plugin/editorconfig.vim: function! s:ApplyConfig(bufnr, config) abort
              endif
          endif