encodeFS is not documented

[joeyh]

I noticed that encodeFS lacks haddock documentation about what it does, eg see here:
https://hackage.haskell.org/package/filepath-1.5.4.0/docs/System-OsPath.html#v:encodeFS

By process of elimination on the 3 strategies that the documentation discusses, I was able to guess that it mimics the behavior of the base library.

I think this should be documented, like decodeFS is.

[hasufell]

Hmm

filepath/System/OsPath/Internal.hs

Lines 69 to 80 in a31bf53

	-- | Like 'encodeUtf', except this mimics the behavior of the base library when doing filesystem
	-- operations, which is:
	--
	-- 1. on unix, uses shady PEP 383 style encoding (based on the current locale,
	-- but PEP 383 only works properly on UTF-8 encodings, so good luck)
	-- 2. on windows does permissive UTF-16 encoding, where coding errors generate
	-- Chars in the surrogate range
	--
	-- Looking up the locale requires IO. If you're not worried about calls
	-- to 'setFileSystemEncoding', then 'unsafePerformIO' may be feasible (make sure
	-- to deeply evaluate the result to catch exceptions).
	encodeFS :: FilePath -> IO OsPath