Documentation of toTitle needs update

It appears the change proposed in issue 167 got committed so that title-casing only takes place after spaces. However, the documentation still reads: "The first letter of the input is converted to title case, as is every subsequent letter that immediately follows a non-letter".

[Bodigrim]

I think the easiest thing to do is to quote in haddocks a reference (but slow) impementation of toTitle:

text/tests/Tests/Properties/Text.hs

Lines 142 to 148 in 02ee677

	referenceToTitle _ [] = []
	referenceToTitle False (y : ys)
	| C.isLetter y = C.toUpper y : referenceToTitle True ys
	| otherwise = y : referenceToTitle False ys
	referenceToTitle True (y : ys)
	| C.isLetter y = C.toLower y : referenceToTitle True ys
	| otherwise = y : referenceToTitle (not (C.isSpace y)) ys