V2 of LiveText: pumped generator follow-up (#20649)
#20177, supersedes #20216.
Summary of the issue:
After #20177:
It is impossible to tell whether lines have been skipped during large text floods;
Copyright and attributions were outdated or missing.
Description of how this pull request fixes the issue:
This PR:
Updates copyright and attribution;
Adds a "beep for skipped lines" option to terminal programs settings.
