fix #1510 ace_invalid appears on correct diff

lib/ace/mode/_test/tokens_diff.json

@@ -54,7 +54,7 @@
    "start"
 ],[
    "start",
-  ["invalid"," "]
+  ["text"," "]
 ],[
    "start"
 ],[
@@ -87,7 +87,7 @@
    "start"
 ],[
    "start",
-  ["invalid"," "]
+  ["text"," "]
 ],[
    "start"
 ],[
@@ -195,7 +195,7 @@
    "start"
 ],[
    "start",
-  ["invalid"," "]
+  ["text"," "]
 ],[
    "start"
 ],[
@@ -265,7 +265,7 @@
    "start"
 ],[
    "start",
-  ["invalid"," "]
+  ["text"," "]
 ],[
    "start"
 ],[
@@ -298,7 +298,7 @@
    "start"
 ],[
    "start",
-  ["invalid"," "]
+  ["text"," "]
 ],[
    "start"
 ],[

lib/ace/mode/_test/tokens_lsl.json

@@ -492,4 +492,4 @@
   ["paren.rparen.lsl","}"]
 ],[
    "start"
-]]
+]]

lib/ace/mode/diff_highlight_rules.js

@@ -88,6 +88,9 @@ var DiffHighlightRules = function() {
             }, {
                 regex: "^Index.+$",
                 token: "variable"
+            }, {
+                regex: "^\\s+$",
+                token: "text"
             }, {
                 regex: "\\s*$",
                 token: "invalid"