Need to consider making copy pasting multi line work with repl.

[congwenma]

For someone starting on elm like me, its painful how many times i've used multicursor to append \ to end of repl lines to test how they work.

[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.