Split the tfvars handling into a separate syntax file

[rchl]

The main syntax no longer handles the .tfvars extension. Handling of
.tfvars is now done by the new syntax file which also assigns a new
source.terraform-vars scope instead of the previous source.terraform.

This change is to allow for differentiating .tfvars and .tf files when
using a terraform-ls language server.

The .tmLanguage syntax files are not changed in the same way as those
don't support including other syntaxes so would have to be duplicated
instead. And since those are long obsolete (in ST at least), I didn't
see much point in doing anything with them.

Fixes #49

[rchl]

The .tmLanguage syntax files are not changed in the same way as those
don't support including other syntaxes

Not 100% sure about that... If the including is possible then I could consider handling those too.

As for tests for tfvars file, I've just duplicated the existing one. That new syntax test file could be trimmed to only include tests for features that are specific to tfvars files but the syntax supports everything anyway so not sure.

[radeksimko]

The .tmLanguage syntax files are not changed in the same way as those don't support including other syntaxes so would have to be duplicated instead.

That's sad but understandable, given the age of the format and its fading support in ST.

One more question:

Is there any convention for the *.sublime-settings and *.sublime-syntax files? I would expect these to follow Language ID, rather than file extensions? i.e. I'd expect terraform-vars.sublime-settings and terraform-vars.sublime-syntax, rather than tfvars.

[radeksimko]

Thanks for the PR.

I can confirm that it works nicely with the LSP package:

[radeksimko]

Worth noting that I had to update the client settings within the LSP plugin settings:

	"terraform":
		{
			"enabled": true,
			"languages": [
				{
					"languageId": "terraform",
					"document_selector": "source.terraform"
				},
				{
					"languageId": "terraform-vars",
					"document_selector": "source.terraform-vars"
				}
			],
			"syntaxes":
			[
				"Packages/Terraform/Terraform.sublime-syntax"
			],
			"command": [
				"terraform-ls",
				"serve"
			],
		}

[rchl]

Created sublimelsp/LSP-terraform#1 for updating LSP-terraform.

(You've accidentally used typescript language ID in your config)

[rchl]

BTW. In ST4 it should work to remove the languages and syntaxes settings and use "selector": "source.terraform | source.terraform-vars" instead.