Duplicated `"` in SISSL-1.2 standard license header template

The SISSL-1.2 ([here](https://github.com/spdx/license-list-data/blob/d8b92c55d6e67244e00dc8c18a7dc23a4a463b65/jsonld/SISSL-1.2.jsonld#L41) standard license header template contains duplicated `\"\"` in `<<var;name=\"contributor\";original=\"__________________________________\"\";match=\".+\">>\n\n` right at the end of the template.