Strip trailing newline from address book entries without names

When the list of completions from the external command doesn't have
associated contact names, the email address we attempt to parse was
being terminated with a newline. Now, we strip the trailing newline if
present.

completer/completer.go

@@ -138,7 +138,10 @@ func readCompletions(r io.Reader) ([]string, error) {
 			return nil, err
 		}
 		parts := strings.SplitN(line, "\t", 3)
-		if addr, err := mail.ParseAddress(parts[0]); err == nil {
+		addr, err := mail.ParseAddress(strings.TrimSpace(parts[0]))
+		if err != nil {
+			return nil, err
+		}
 		if len(parts) > 1 {
 			addr.Name = strings.TrimSpace(parts[1])
 		}
@@ -148,7 +151,6 @@ func readCompletions(r io.Reader) ([]string, error) {
 		}
 		completions = append(completions, decoded)
 	}
-	}
 }
 
 func decodeMIME(s string) (string, error) {