Some nits.
https://codereview.appspot.com/581570043/diff/563450043/scm/markup-macros.scm File scm/markup-macros.scm (right): https://codereview.appspot.com/581570043/diff/563450043/scm/markup-macros.scm#newcode419 scm/markup-macros.scm:419: "Lookup procedure in the current module, or return #f" s/Lookup/Look up/ https://codereview.appspot.com/581570043/diff/563450043/scm/markup-macros.scm#newcode427 scm/markup-macros.scm:427: "Return (PROC . SIG) for a markup command, or return #f" Mhmm, what is 'PROC', what is 'SIG'? For me, this doc string is still too terse... https://codereview.appspot.com/581570043/
