Auto merge of #5788 - Leulz:shadow-unrelated-fix-rhs, r=flip1995

Removing RHS snippet from SHADOW_UNRELATED message.

Fixes #5703

I am not sure if I reinvented the wheel here, but I could not really find a snippet function that did this truncation, so I created the function. Please tell me if there was a more obvious way to do this, I am new here. :smile:

changelog: Truncates multi-line RHS in shadow_unrelated message if it has more than 5 lines.