Fix formal syntax of text-decoration-skip to fit current CSS Text Decoration Module Level 3 [CR]

[CSS Text Decoration Module Level 3](https://www.w3.org/TR/css-text-decor-3/#text-decoration-skip-property)

Author: toptalo

src/css/Properties.js

@@ -435,8 +435,8 @@ var Properties = module.exports = {
     "text-decoration-color"             : "<text-decoration-color>",
     "text-decoration-line"              : "<text-decoration-line>",
     "text-decoration-style"             : "<text-decoration-style>",
-    "text-decoration-skip"              : "none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]",
-    "-webkit-text-decoration-skip"      : "none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]",
+    "text-decoration-skip"              : "none | [ objects || spaces || ink || edges || box-decoration ]",
+    "-webkit-text-decoration-skip"      : "none | [ objects || spaces || ink || edges || box-decoration ]",
     "text-emphasis"                     : 1,
     "text-height"                       : 1,
     "text-indent"                       : "<length> | <percentage>",

tests/css/Validation.js

@@ -1494,16 +1494,16 @@ var YUITest = require("yuitest"),
         valid: [
             "none",
             "objects",
+            "spaces",
+            "ink",
             "edges",
             "box-decoration",
-            "spaces",
-            "leading-spaces trailing-spaces",
-            "objects leading-spaces trailing-spaces",
-            "objects edges box-decoration"
+            "objects spaces ink"
         ],
 
         invalid: {
-            "foo" : "Expected (none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]) but found 'foo'."
+            "none objects" : "Expected end of value but found 'objects'.",
+            "foo" : "Expected (none | [ objects || spaces || ink || edges || box-decoration ]) but found 'foo'."
         }
     }));
 
@@ -1513,16 +1513,16 @@ var YUITest = require("yuitest"),
         valid: [
             "none",
             "objects",
+            "spaces",
+            "ink",
             "edges",
             "box-decoration",
-            "spaces",
-            "leading-spaces trailing-spaces",
-            "objects leading-spaces trailing-spaces",
-            "objects edges box-decoration"
+            "objects spaces ink"
     ],
 
         invalid: {
-            "foo" : "Expected (none | [ objects || [ spaces | [ leading-spaces || trailing-spaces ] ] || edges || box-decoration ]) but found 'foo'."
+            "none objects" : "Expected end of value but found 'objects'.",
+            "foo" : "Expected (none | [ objects || spaces || ink || edges || box-decoration ]) but found 'foo'."
         }
     }));