Strip prompts even if the prompt isn't present on the first line....
Strip prompts even if the prompt isn't present on the first line.
Users (including me) often copy and paste examples from just after the first
prompt. This checks for prompts in the first two lines of a block, but if they
aren't found there, it will ignore prompt-like prefixes in later lines, to
minimise interference with multi-line strings etc.
Closes gh-3206