Can a corded electric trimmer also edge?

Many can. The Black+Decker ST8600 and BESTE620 both rotate the head 180° to convert to a wheeled edger, and reviewer feedback at Lowe's, Home Depot and Amazon is generally positive on edge quality for residential walkways. If edging is the primary job, a dedicated blade edger like the WORX WG896 is a separate (more capable) tool class.