Log Message:
gnucash-docs: update to 4.12.

 4.12  - 25 September 2022
        o Major revision of the Online Quote Retrieval (Finance::Quote) section.
        o Enumerate figure files in CMakeLists so that invalid references will
          error out at build time and fail CI.
        o Install according to the XDG document spec instead of the very
          obsolete GHelp scheme.
        o Manual C: adjust image width
        o Improve GPL link
        o Simplify ulink tags
        o Create several new DocBook entities.
        o Manual: remove superfluous "Help_" from file names
        o Add option to enable/disable html install rules
          It's only used on MacOS and interferes with the linux distribution
          builds. The option is enabled by default on MacOS and disabled on
          other platforms.
        o Manual: Minor structural cleanup of GUIMenus (C, de)
        o gnc-dobookx.dtd: Mention predefined entities
        o Return doc crosslink to draft.
        o New and Updated Translations: German