Currently, when serializing a `Float value using to_string, the Printf.sprintf is used with the format hard-coded to "%.16g":

In practice this results in the following:

# let x = 94.96 in
  string_of_float x,
  Printf.sprintf "%0.15g" x,
  Printf.sprintf "%0.16g" x,
  Yaml.to_string (`Float x);;
- : string * string * string * string Yaml.res =
("94.96", "94.96", "94.95999999999999", Ok "94.95999999999999\n")

Would it be possible introduce a way to control the float format precision? Alternatively, I propose hard-coding "%0.15g" would work better in terms of readability.

Note: of_json uses Stdlib.string_of_float, which itself uses "%0.12g" as the format.