Add spread operator to the @operator list for ECMAScript languages (#35360)

Previously, this was the one thing that could not be styled properly in
ecmascript languages in the zed config, because it was not able to be
targeted.

Now, it is added alongside other operators. This has been tested and
works as expected.

Release Notes:

- N/A

crates/languages/src/javascript/highlights.scm

@@ -146,6 +146,7 @@
   "&&="
   "||="
   "??="
+  "..."
 ] @operator
 
 (regex "/" @string.regex)