rfc: should each chapter lead with questions

[dwmkerr]

If you look at a title like 'The If Statement' the chapter seems boring.

But what about if the chapter started with:

By the end of this chapter you'll know why:

• You should put quotes around variables in an if statement
• The magic shell syntax to write a test command with just two characters

I.e. not giving the game away, but hinting to new and advanced users what they might discover.