only append newline when there is none
only append newline when there is none

same implementation as in sourcemaps

nsams/koala-framework,nsams/koala-framework,koala-framework/koala-framework,yacon/koala-framework,yacon/koala-framework,kaufmo/koala-framework,nsams/koala-framework,koala-framework/koala-framework,kaufmo/koala-framework,yacon/koala-framework,kaufmo/koala-framework