* scm/chord-name.scm: don't export anything from chord module.

* scm/chord-name.scm: don't export anything from chord module.

* input/test/american-chords.ly: idem

* input/test/banter-chords.ly (texidoc): idem

* input/test/Cc-chords.ly: add breakage notes.

* Documentation/user/refman.itely (Text markup): rewrite manual section.

* scm/chord-name.scm: complete new markup usage

* scm/grob-description.scm (all-grob-descriptions): use new markup
texts by default