Fix multi line formatting

[maxRN]

No description provided.

[rgrinberg]

Is it possible to introduce the Block_string only in the CST?

[maxRN]

Not without further work: Dune_sexp.parse parses all values into a list of Encoded.t which are actually Ast.t values and turns those back into Cst.t. So if we don't have a Block_string in the AST we lose precision so to speak, because we would turn a Cst.Block_string into a Ast.Quoted_string and then we can no longer know if it's really a Quoted_string or a Block_string.

Maybe we could somehow adjust the parsing function and add an option to directly return it as Cst.t values.

[nojb]

Why not change string by a richer abstract type that would remember whether it came from a quoted string or a blocked string, as well as having a to_string to get the underlying string. The type could also include the Loc.t.

[maxRN]

I really like this idea and will probably implement it like this, but there is more work to be done for block strings that are also templates.