Log Message:
Update gnucash-docs to 2.6.12.

Concurrent with the release of Gnucash 2.6.12 we're pleased to also release a \ 
new version 2.6.12 of the companion Help and Tutorial and Concepts Guide.

   New Portuguese Translations from Pedro Albuquerque!
   Bug 639776 - Update instructions for updating quote prices by cron.
   Bug 649283 - Add links to where common report preferences are set.
   Bug 728722 - Setting number format details appear wrong in Help, section \ 
10.3.4. Counters Book Options Tab
   Bug 729265 - Update documentation for Invoice and Bill payments to reflect \ 
the new features.
   Bug 761025 - Add missing sect Guide ch2.8: New book options in New Acct Hierarchy.
   Bug 762088 - Remove Section 9.4.3 From Guide that offered simplistic advice \ 
about money and life that does nothing to explain GnuCash functionality or use.
   Bug 762656 - Add note to Guide section 2.3.3 For Column Widths