chore: remove colon in stylus of NavLinks (#299)

Author: meteorlxy

lib/default-theme/NavLinks.vue

@@ -109,7 +109,7 @@ export default {
     &:hover, &.router-link-active
       color $accentColor
   .nav-item
-    cursor: pointer
+    cursor pointer
     position relative
     display inline-block
     margin-left 1.5rem