Typo fix s/returns a label of current breakpoint, [list of breakpoints]/returns current breakpoint (for instance `small`) among a [list of breakpoints]/
Typo fix s/returns a label of current breakpoint, [list of breakpoints]/returns current breakpoint (for instance `small`) among a [list of breakpoints]/

As requested by jpetitcolas at https://github.com/marmelab/EventDrops/pull/249#discussion_r202075969
marmelab/EventDrops