JShell: Request for ideas: Editing multiline snippets, adding lines

[Robert Field]

A fix about to go back to JDK 12 (see JLine 3 review discussion) provides a significant improvement when editing multiline snippets — they are treated as an integral unit — with WYSIWYG-ish interaction.

There is however one limitation:  Since <return> has its legacy action of accepting the input, there is no way with line editing to add a line within a multiline snippet.  

It would seem that a different input is needed to add a line (unless I’m missing something).  Suggestions for that keystroke are herein solicited.

Thanks,
Robert