* lily/parser.yy (markup): in markups, { .. } without command

* lily/parser.yy (markup): in markups, { .. } without command
before are also flattened, ie \line must be explicitely used.

* Documentation/user/changing-defaults.itely:
* Documentation/user/notation.itely:
* input/wilhelmus.ly:
* input/regression/instrument-name-markup.ly:
* input/regression/markup-score.ly:
* input/regression/new-markup-scheme.ly:
* input/regression/new-markup-syntax.ly:
* input/test/coriolan-margin.ly: use \line in markups where
appropriate