erp5_api_style: fix Content-Type for hyperschema

bt5/erp5_api_style/SkinTemplateItem/portal_skins/erp5_api_style/jIOWebSection_getAPIJSONHyperSchema.py

@@ -29,6 +29,9 @@ data["links"] = data["links"] + populateLinks("post", "post/", context.ERP5Site_
 data["links"] = data["links"] + populateLinks("put", "put/", context.ERP5Site_getAllActionListForAPIPut())
 data["links"] = data["links"] + populateLinks("allDocs", "allDocs/", context.ERP5Site_getAllActionListForAPIAllDocs())
 
+if context.REQUEST is not None:
+  context.REQUEST.RESPONSE.setHeader("Content-Type", "application/json")
+
 import json
 return json.dumps(
   data,