Fix syntax for ellipsis helper

Problem: The suggested ellipsis syntax breaks the handlebars expression due to an additional comma.

Solution: Removed the comma from the help text,

packages/string-templates/manifest.json

@@ -625,7 +625,7 @@
         "length"
       ],
       "numArgs": 2,
-      "example": "{{ellipsis 'foo bar baz', 7}} -> foo bar…",
+      "example": "{{ellipsis 'foo bar baz' 7}} -> foo bar…",
       "description": "<p>Truncates a string to the specified <code>length</code>, and appends it with an elipsis, <code>…</code>.</p>\n"
     },
     "hyphenate": {