Fix for DevTools failed to load SourceMap

[ModelEarth]

To fix the following warning:

DevTools failed to load SourceMap: Could not load content for http://localhost:8887/localsite/js/showdown.min.js.map: HTTP error: status code 404, net::ERR_HTTP_RESPONSE_CODE_FAILURE

Replace the # symbol in the last line: //# sourceMappingURL=showdown.min.js.map

Should be: // sourceMappingURL=showdown.min.js.map

The warning appears in the inspector. It's not visible to all users.