[dox] Text describing Sections in Documentation Generator page needs improvement

[Andre Artus]

I have been racking my brain to find a suitable replacement for 
the section description, I would appreciate your critique.

"A section is a block of text that is processed by the document 
generator. There are only two unlabeled sections, summary and 
description, all other sections are identified by a label (or 
name). A section label starts with the first non-blank 
character[1] on a line and continues until terminated by a colon 
(:).

Details of each kind of section follow"


1. This is technically not true, as the first non-blank character 
could be an asterisk. As far as  I can see the section labels 
follow the same rules as other identifiers. But, according to the 
description above the following,

/**
* 7^%$#@!  ][|:
*/

would be a valid section name/label --with the value "* 7^%$#@!  
][|"-- which seems questionable to me.

I think we should tighten up the rules regarding section labels.