Remove newlines inside & inbetween block-elements for better readability about htmlarkdown

[EvitanRelta]

When prototyping the table conversion, I discovered that this HTML:

<table forcehtml>
  <thead>
    <tr>
      <th>h1</th>
      <th>h2</th>
      <th>h3</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>c1</td>
      <td>c1</td>
      <td>c3</td>
    </tr>
    </tr>
  </tbody>
</table>

which converted to this markdown:

<table>
  <tr>
    <th>
      h1
    </th>
    
    <th>
      h2
    </th>
    
    <th>
      h3
    </th>
  </tr>
  
  <tr>
    <td>
      c1
    </td>
    
    <td>
      c1
    </td>
    
    <td>
      c3
    </td>
  </tr>
</table>

incorrectly renders in GitHub as shown:

<th>
  h2
</th>

<th>
  h3
</th>

<td>
  c1
</td>

<td>
  c3
</td>

h1
c1

It can be fixed by at least removing the blank lines inbetween the inner <tr> / <th> / <td> tags:

<table>
  <tr>
    <th>
      h1
    </th>
    <th>
      h2
    </th>
    <th>
      h3
    </th>
  </tr>
  <tr>
    <td>
      c1
    </td>
    <td>
      c1
    </td>
    <td>
      c3
    </td>
  </tr>
</table>

Thus, this issue's label is being changed to bug.