bob: Mention linebreak handling

In particular, the canonical-data.json lists the example

    \nDoes this cryogenic chamber make me look fat?\nNo.

To which bob should evidently respond simply

    Whatever

https://github.com/exercism/problem-specifications/blob/0bc49850f24ff35b56c4093f7fd664d507b3fa22/exercises/bob/canonical-data.json#L184-L192

Author: oleks

exercises/bob/instructions.md

@@ -17,3 +17,5 @@ Bob only ever answers one of five things:
   The convention used for silence is nothing, or various combinations of whitespace characters.
 - **"Whatever."**
   This is what he answers to anything else.
+
+Bob always responds with a single sentence, regardless of the number of lines in the input.