Revert "fix: Newline printing improperly in some situations"

This reverts commit 33cab3a.

progressbar.go

@@ -326,7 +326,7 @@ func DefaultBytes(maxBytes int64, description ...string) *ProgressBar {
 		OptionThrottle(65*time.Millisecond),
 		OptionShowCount(),
 		OptionOnCompletion(func() {
-			fmt.Printf("\n")
+			fmt.Fprint(os.Stderr, "\n")
 		}),
 		OptionSpinnerType(14),
 		OptionFullWidth(),
@@ -375,7 +375,7 @@ func Default(max int64, description ...string) *ProgressBar {
 		OptionShowCount(),
 		OptionShowIts(),
 		OptionOnCompletion(func() {
-			fmt.Printf("\n")
+			fmt.Fprint(os.Stderr, "\n")
 		}),
 		OptionSpinnerType(14),
 		OptionFullWidth(),