add syntax highlighting for .stylelintignore (#240)

package.json

@@ -82,6 +82,14 @@
 				"fileMatch": "**/.stylelintrc*",
 				"url": "http://json.schemastore.org/stylelintrc.json"
 			}
+		],
+		"languages": [
+			{
+				"id": "ignore",
+				"filenames": [
+					".stylelintignore"
+				]
+			}
 		]
 	},
 	"scripts": {

test/.stylelintignore

@@ -0,0 +1 @@
+

test/index.js

@@ -1,6 +1,8 @@
 /* eslint-disable node/no-unpublished-require */
 'use strict';
 
+const {join} = require('path');
+
 const test = require('tape');
 const {extensions, workspace, window} = require('vscode');
 
@@ -33,6 +35,12 @@ const run = () => test('vscode-stylelint', async t => {
 		'should be activated when the open file is CSS.'
 	);
 
+	t.equal(
+		(await workspace.openTextDocument(join(__dirname, '.stylelintignore'))).languageId,
+		'ignore',
+		'should add syntax highlighting to .stylelintignore.'
+	);
+
 	t.end();
 });