describe-function should fold, not wrap

[jidanni]

On a e.g., 80 column terminal this and any other longish named item
wraps unnecessarily: (describe-function (quote
font-lock-match-c-style-declaration-item-and-skip-to-next))

The problem is that describe-function was invented before the age of
long function names. It's first line of output should be folded, not
wrapped.