feature request: whitespace cleaning quasiquoter

[goertzenator]

This whitespace cleaning quasiquoter is handy and might make a nice addition to this package. It...

• Removes leading and trailing blank lines.
• Removes trailing whitespace.
• Removes common indent.

Existing quasiquoters pressure you to eliminate whitespace by aligning the quoted text to the left margin which usually conflicts with the ambient indent level of the code. This qq removes indent whitespace for you and lets you indent normally.