Error when extracting confidence in JSON

[dgarijo]

For some reason, the confidence sometimes is found not as a list, but as a double list:

"description": [
        {
            "excerpt": "Tool to transform ontology conceptualizations made with diagrams.net into OWL code.\r\n\r\nThe conceptualizations should follow the <a href=\"https://chowlk.linkeddata.es/notation.html\">Chowlk visual notation</a>. Please visit the specification for more details.\r\n\r \n",
            "confidence": [
                [
                    0.9370490666739703
                ]
            ],
            "technique": "Supervised classification",
            "originalHeader": "Chowlk Converter"
        },

This is problematic for some parsers. It should be a single list.

[dgarijo]

Did not add a test for this one, as it's a change in the output format