Thanks Rob! It worked, but using Shift + Alt + Enter. It also works if you don't use a formula for the body line item and you just enter the text and use Shift + Alt + Enter to add the breaks. I think this last option is better, as you are not limited by a fixed number of paragraphs.
I'm attempting to reproduce this line break line item, but I'm not having any luck on my Windows 10 Enterprise laptop (version 1909, OS build 18363.959).
Enter and Shift-Enter confirm entry of the line item (equivalent to clicking the green checkbox icon at far right), while other combinations of [Alt, Ctrl, Shift]-Enter have no effect, i.e., Ctrl-Enter, Alt-Enter, Ctrl-Alt-Enter, Ctrl-Shift-Enter, Alt-Shift-Enter, Ctrl-Alt-Shift-Enter don't do anything.
from Notepad will show the desired input in the cell, but gives a "The formula for 'Module'.'Line Item' is invalid:" error.
Is there some other way to capture these line breaks?
To be crystal clear, I'm holding down the Alt and Shift keys while pressing Enter with my cursor between the quotes and with the checkmark icon visible at right and getting no response from the editing bar (or from the computer at all, really). I tried it holding down Alt first and holding down Shift first (the sequence shouldn't really matter, in my experience) with indistinguishable results.
Do you perhaps know of any alternate ways to get a line break into a model cell?
It may also be noteworthy that my target module and line item are dimensionless, but the module has a number of user-dimensioned subsidiary view items to feed some textlists to generate the To/Cc/Bcc listings.
I want to take a moment to thank @rob_marshall for his above-and-beyond help on this issue.
The key problem I had in reproducing this solution above was that I was making a formula entry instead of an entry into the data cell. I wasn't able to enter a line break in a formula to extend across all relevant dimensions, but I was able to make a line break entry in a data cell outside of Blueprint view. On my Windows 10 machine, I was able to make the entry not with Alt-Shift-Enter, but rather with Ctrl-Alt-Enter. Storing multiple line breaks in a single cell wasn't effective, but text joining with it more than once worked.