feat(attr-sort): sort unknown attributes alphabetically

Previously unknown attributes were just ignored. Now they get sorted alphabetically.

BREAKING CHANGE: HTMLHint will now throw an error if unkown attributes are not sorted.

fix htmlhint#661

Author: chrisguttandin

Diff for: src/core/rules/attr-sorted.ts

@@ -34,7 +34,7 @@ export default {
       const originalAttrs = JSON.stringify(listOfAttributes)
       listOfAttributes.sort((a, b) => {
         if (orderMap[a] == undefined && orderMap[b] == undefined) {
-          return 0
+          return a.localeCompare(b)
         }
         if (orderMap[a] == undefined) {
           return 1

Diff for: test/rules/attr-sorted.spec.js

@@ -16,14 +16,24 @@ describe(`Rules: ${ruleId}`, () => {
     expect(messages[0].message).toContain('["id","class","title"]')
   })
 
-  it('Attribute unsorted tags that are unrecognizable should not throw error', () => {
-    const code = '<div img="image" meta="meta" font="font"></div>'
+  it('Attribute sorted tags that are unrecognizable should not throw error', () => {
+    const code = '<div font="font" img="image" meta="meta"></div>'
 
     const messages = HTMLHint.verify(code, ruleOptions)
 
     expect(messages.length).toBe(0)
   })
 
+  it('Attribute unsorted tags that are unrecognizable should throw error', () => {
+    const code = '<div img="image" meta="meta" font="font"></div>'
+
+    const messages = HTMLHint.verify(code, ruleOptions)
+
+    expect(messages.length).to.be(1)
+    expect(messages[0].rule.id).to.be(ruleId)
+    expect(messages[0].message).to.contain('["img","meta","font"]')
+  })
+
   it('Attribute unsorted of tags of various types should throw error', () => {
     const code = '<div type="type" img="image" id="id" font="font"></div>'