Update html_updateHeadings.sh
    
        - In this commit the table of content is updated using headings
          but nesting isn't as expected yet. 
          
          We need to change the way to parse, instead of making a full
          search for al h1, then h2, later h3 and so on, we need to look
          for all h1 and headings inside it but until finding the next
          heading of the same level. The same thing repeats for h2, h3,
          h4, and h5 recursively. We consider h6 the last possibility so
          don't look for h7.
    
          For example:
    
          inside h1 can be: h2, h3, h4, h5, h6
          inside h2 can be: h3, h4, h5, h6
          inside h3 can be: h4, h5, h6
          inside h4 can be: h5, h6
          inside h5 can be: h6