fix(xstream-typings): fix HTTPSource.select() return
fix(xstream-typings): fix HTTPSource.select() return

Had a wrong return type.

ntilwalli/cyclejs,staltz/cycle,maskinoshita/cyclejs,feliciousx-open-source/cyclejs,cyclejs/cycle-core,usm4n/cyclejs,cyclejs/cycle-core,ntilwalli/cyclejs,feliciousx-open-source/cyclejs,ntilwalli/cyclejs,maskinoshita/cyclejs,cyclejs/cyclejs,staltz/cycle,usm4n/cyclejs,usm4n/cyclejs,cyclejs/cyclejs,feliciousx-open-source/cyclejs,feliciousx-open-source/cyclejs,ntilwalli/cyclejs,maskinoshita/cyclejs,maskinoshita/cyclejs,cyclejs/cyclejs,cyclejs/cyclejs,usm4n/cyclejs