[Bug] Assumes first row is always table header even if it is not

[roniemartinez]

The script:

print(
        html2text.html2text(
            """
            <table>
            <tbody>
            <tr><td>item a</td><td>item b</td></tr>
            <tr><td>item c</td><td>item d</td></tr>
            </tbody>
            </table>
            """
        )
    )

Results to:

item a| item b  
---|---  
item c| item d

• Version by html2text --version: 2020.1.16
• Test script
• Python version python --version: Python 3.10.2