Merge branch 'fix_double_boost_chant_hymn' into 'master'

fix talent level of chants & hymns boosted by difficulty twice.

In high difficulties, Chant of XXX or Hymn of XXX has higher level than Chant Acolyte or Hymn Acolyte accordingly, because they get double boost from difficulty.
This merge request add "no_difficulty_boost" tag to Chant Acolyte and Hymn Acolyte to avoid double boost.

See merge request !743