feat($default-theme): vue-styled deleted & inserted code

Author: ulivz

packages/@vuepress/theme-default/styles/code.styl

@@ -6,6 +6,11 @@
     font-size 0.85em
     background-color rgba(27,31,35,0.05)
     border-radius 3px
+    .token
+      &.deleted
+        color #EC5975
+      &.inserted
+        color $accentColor
 
 .content
   pre, pre[class*="language-"]
@@ -125,6 +130,6 @@ div[class~="language-python"]:before
 
 div[class~="language-bash"]:before
   content "sh"
-  
+
 div[class~="language-php"]:before
   content "php"