Prompt visible during multiline typing animation

[jcubic]

Issue summary

If you echo a multiline string, after each line the prompt is visible.

Expected behavior

prompt should not be visible

Actual behavior

prompt is visible

Steps to reproduce

1. CodePen demo
2. Observe the prompt

Browser and OS

N/A

Additional notes

This can be fixed the same as with a sequence of animations by setting the prompt to an empty string at the beginning of the animation and restoring it after.