It has been a quiet day in Washington. A routine day for our lawmakers, but a frustrating one for newsmen. No doubt it is this lull which has prompted headline hungry reporters to speculate upon the sudden departure of Senator Dean Edwards. He was reported to have left the senate chamber immediately after recess was called, and gone directly to Washington national airport. This too may be a routine journey, but usually when he leaves Washington, there's news in the offing. Right now, he's disputing the responsibility for the education of migratory workers' children.