Add unsafeTextWithLength

[reixn]

Add unsafeTextWithLength according to #103

[sjakobi]

Thanks for the PR! :)

I have a few comments.

There are also some CI failures that need fixes.

[sjakobi]

What's the use case for this function? I don't imagine that wide characters and emojis will typically exist in the form of a lazy Text values?!

If there's no obvious use case, I'd prefer not to add this function.

[sjakobi]

The documentation should clarify why and how this function is useful for dealing with wide characters and emojis.

[sjakobi]

I think this definition is a bit misplaced between these Pretty instances. I suggest placing it below unsafeTextWithoutNewlines.

[sjakobi]

The Text invariants need to be handled in some way too:

prettyprinter/prettyprinter/src/Prettyprinter/Internal.hs

Lines 153 to 159 in 0dbe08f

	-- | Invariants: at least two characters long, does not contain '\n'. For
	-- empty documents, there is @Empty@; for singleton documents, there is
	-- @Char@; newlines should be replaced by e.g. @Line@.
	--
	-- Since the frequently used 'T.length' of 'Text' is /O(length)/, we cache
	-- it in this constructor.
	| Text !Int !Text

[reixn]

I think that invariant should be handled by user because single character may have different length.