Remove unwanted trailing comma. Resolves issue #1670.

Author: dpvc

unpacked/jax/output/CommonHTML/jax.js

@@ -81,7 +81,7 @@
     ".mjx-math":   {
       "display":         "inline-block",
       "border-collapse": "separate",
-      "border-spacing":  0,
+      "border-spacing":  0
     },
     ".mjx-math *": {
       display:"inline-block",