XML docs: layout fixes for enum-lists and docs and button-accessibility

[jkowalleck]

• Added a readme acknowledging that we dont have an info which version of the xs3p was used as a base
• Put "invisible" text in the circle buttons - for screen readers
• Fixed a rendering bug for long value lists: there was a line break after EVERY item after the 5th.
  Converted the old >5 to a %5 = 0 to have a line-break after each 5 items ... this works well for the pre area.
  For the non-pre areas, I've added a <wb/> so the content may break when needed.
  The entire pre-wrapped behavior is configurable via param breakEnumListAfterN.
  Remark: using a break before the or-operator/pipe (|) as this is better readable on long lists
• fixed the issue with duplicate docs text

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old:

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