Document primitive string literals and desugaring of string literals
This MR addresses #17474 (closed) and #17974 (closed).
This doesn't mention optimization issues on primitive string literals (e.g. #11312) or rewrite rules in GHC.CString
, but they can be added later.
I placed the document under "Language extensions > Unboxed types and primitive operations" section, but "Language extensions > Literals" or "Language extensions > Syntax > The magic hash" might be good alternatives.
Lastly, my English might not be good. Suggestions are welcome!