[BUG] [Java] [html2] Response headers get '-' replaced with 'Minus'

Created by: ilgrosso

The following JSON excerpt:

"400" : {
            "description" : "An error occurred; HTTP status code can vary depending on the actual error: 400, 403, 404, 409, 412",
            "headers" : {
              "X-Application-Error-Code" : {
                "description" : "Error code",
                "schema" : {
                  "type" : "string"
                }
              },
              "X-Application-Error-Info" : {
                "description" : "Error message(s)",
                "schema" : {
                  "type" : "string"
                }
              }
            }

generates the following Response Headers, with html2: