fixed English typos

Mostly affects comments; very few code changes:

dire.swing.HScrollbarPolicy.{Alyways => Always}
dire.swing.VScrollbarPolicy.{Alyways => Always}
dire.DataSourceFunctions.{createInpure => createImpure, signalSrcInpure => signalSrcImpure, eventSrcInpure => eventSrcImpure}