IOContext not properly set for stdout, disables ANSI colors

[danielwe]

Since #2148 the stdout capture window supports ANSI terminal colors, and :color => true is set in default_stdout_iocontext as seen here:

Pluto.jl/src/runner/PlutoRunner/src/PlutoRunner.jl

Lines 1007 to 1012 in 216451c

	const default_stdout_iocontext = IOContext(devnull,
	:color => true,
	:limit => true,
	:displaysize => (18, 75),
	:is_pluto => false,
	)

However, when querying stdout in a Pluto cell, :color is set to false, so well-behaved Julia code will not print colors. MWE: printstyled("hello"; color=:red). A workaround is to wrap stdout in your own IOContext and set :color => true, but this should not be necessary.

(Please take this screenshot in place of a video. Nothing dynamic here.)

Notebook file: https://gist.github.com/danielwe/0663e49fbfb2219b2230d3fe2092c097

Using Pluto 0.19.39 on Julia 1.10.1