Add comments to code related to page breaking/layout (issue 563630043 by address@hidden)

[lemzwerg]

LGTM.  Please feel free to ignore (most of) my remarks if you consider
such nitpicking as unnecessary :-)


https://codereview.appspot.com/563630043/diff/571770043/lily/include/page-breaking.hh
File lily/include/page-breaking.hh (right):

https://codereview.appspot.com/563630043/diff/571770043/lily/include/page-breaking.hh#newcode107
lily/include/page-breaking.hh:107: Read the large commennt at the top of
page-breaking.cc for context.
s/commennt/comment/

https://codereview.appspot.com/563630043/diff/571770043/lily/include/page-spacing.hh
File lily/include/page-spacing.hh (right):

https://codereview.appspot.com/563630043/diff/571770043/lily/include/page-spacing.hh#newcode101
lily/include/page-spacing.hh:101: we add lines.  details
details what?  Looks like something is missing accidentally.

https://codereview.appspot.com/563630043/diff/571770043/scm/page.scm
File scm/page.scm (right):

https://codereview.appspot.com/563630043/diff/571770043/scm/page.scm#newcode51
scm/page.scm:51: of layout settings just like markups inside the music"
Final stop missing.

https://codereview.appspot.com/563630043/diff/571770043/scm/page.scm#newcode96
scm/page.scm:96: "Add a annotation at the top to STENCIL and return new
stencil."
s/a/an/

https://codereview.appspot.com/563630043/diff/571770043/scm/page.scm#newcode119
scm/page.scm:119: "add annotations to a stencil, and return result"
Add ... result.

https://codereview.appspot.com/563630043/diff/571770043/scm/paper-system.scm
File scm/paper-system.scm (right):

https://codereview.appspot.com/563630043/diff/571770043/scm/paper-system.scm#newcode38
scm/paper-system.scm:38: "add stencils for notes to the main stencil,
returning the result."
s/add/Add/

https://codereview.appspot.com/563630043/diff/571770043/scm/paper-system.scm#newcode89
scm/paper-system.scm:89: "Y-ext and next-Y-ext are either skyline-pairs
or extents"
Final stop missing.

https://codereview.appspot.com/563630043/