writeall referenced in docs, but doesn't exist

[rofinn]

On line 325 of docs/manual/running-external-programs.rst the example solution is using a writeall(proc, x) function that no longer exists.

[akaysh]

@Rory-Finnegan Should this reference be completely removed or something else is required in its place?
As it is referenced as one of the ways to avoid deadlock by separation or reading and writing operations in the pipeline, I think there should be an existing alternative way to do that.

[rofinn]

@akaysh I think you should just be able to replace writeall(...) with write(...) the deadlock avoidance is due to using readstring vs wait.

[akaysh]

@Rory-Finnegan I found the writeall function in process.jl which asynchronously runs commands using write function.
Is it still required to replace the reference?

[rofinn]

Well it isn't exported, so the example should either be removed or the code should explicitly do a Base.writeall.

[akaysh]

@Rory-Finnegan #19975