fix contradictory example in Conditionals

[mkolodny]

The example in the Conditionals section shows that if...else should be preferred over unless...else for negative conditions. Yet the description above the example says the opposite.
This removes the contradiction so that if...else is preferred in both the description and the example.

[mjrusso]

I think what the first sentence is referring to are statements like these, where the unless is used in postfix form:

# Yes
go() unless stop

# No
go() if not stop

So the sentence could read instead:

Favor unless over if not for negative conditions.

This does contradict the next sentence about unless...else, so it may be best to swap the order of the two sentences, include the example above, and reword the earlier sentence to something like this:

In postfix form, favor unless over if not for negative conditions.

This should preserve the original meaning and be less ambiguous.

[anonomis]

Sux