Fix output type of BQ Hephestos

That application/x-code may actually be the XCode application or something? Whatever, it should be x-gcode...

resources/definitions/bq_hephestos_xl.def.json

@@ -6,7 +6,7 @@
         "visible": true,
         "manufacturer": "BQ",
         "author": "BQ",
-        "file_formats": "text/x-code",
+        "file_formats": "text/x-gcode",
         "platform": "bq_hephestos_platform.stl",
         "platform_offset": [ 0, -82, 0]
     },