fix(no-hashbang-comment): error on files without comments

Author: brettz9

lib/rules/no-hashbang-comment.js

@@ -5,7 +5,7 @@ module.exports = (context, badBrowser) => {
   return {
     'Program:exit' (node) {
       const [comment] = sourceCode.getAllComments();
-      if (comment.type === 'Shebang') {
+      if (comment && comment.type === 'Shebang') {
         context.report(node, `Hashbang comments are not supported in ${badBrowser}`)
       }
     }

test/no-hashbang-comment.js

@@ -9,6 +9,7 @@ ruleTester.run('no-hashbang-comment', rule, {
   valid: [
     {code: '// Regular comment'},
     {code: '/* Regular comment */'},
+    {code: 'noComment;'},
   ],
   invalid: [
     {