Parser: i{n,s}_multiline -> multi
Parser: i{n,s}_multiline -> multi

Some of the handler functions had is_multiline, others had in_multiline,
resulting in a bit of confusion. This eliminates any possible confusion.

jesserayadkins/lily,FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily,FascinatedBox/lily,FascinatedBox/lily,jesserayadkins/lily