`TOML.print` generates invalid TOML on stdout when the values include multiline strings

[palday]

julia> TOML.print(Dict("a" => """x\nx"""))
a = "x\nx"

julia> TOML.parse("""a = "x\nx" """)
ERROR: TOML Parser error:
none:2:-1 error: newline character in single quoted string
  a = "x
       ^ 
Stacktrace:
 [1] parse
   @ ./toml_parser.jl:445 [inlined]
 [2] parse(str::String)
   @ TOML ~/.julia/juliaup/julia-1.10.4+0.aarch64.apple.darwin14/share/julia/stdlib/v1.10/TOML/src/TOML.jl:71
 [3] top-level scope
   @ REPL[99]:1

Interestingly, this seems to only be an issue with stdout and is handled correctly with other IO streams

julia> io = IOBuffer();  TOML.print(io, Dict("a" => """x\nx""")); TOML.parse(seekstart(io))
Dict{String, Any} with 1 entry:
  "a" => "x\nx"

I'm guessing this intersection of two different expectations -- we generally don't include triple quotes for show-type methods going to stdout, but in this particular case, it prevents a simple copy-paste of the generated TOML into other use cases.

julia> versioninfo()
Julia Version 1.10.4
Commit 48d4fd48430 (2024-06-04 10:41 UTC)
Build Info:
  Official https://julialang.org/ release
Platform Info:
  OS: macOS (arm64-apple-darwin22.4.0)
  CPU: 8 × Apple M1
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-15.0.7 (ORCJIT, apple-m1)
Threads: 4 default, 0 interactive, 2 GC (on 4 virtual cores)

[palday]

julia/stdlib/TOML/src/print.jl

Lines 104 to 106 in 594544d

	value isa AbstractString ? (Base.print(io, "\"");
	print_toml_escaped(io, value);
	Base.print(io, "\"")) :

Looks like there's no handling of newlines