bug#35328: [PATCH] Improve documentation around standard error pipes (Bug#35328).

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Cc: 35328@debbugs.gnu.org,
>       Philipp Stephani <phst@google.com>
> Date: Sun, 21 Apr 2019 18:11:47 +0200
> 
> +If @var{stderr} is a buffer, Emacs will create a pipe process, the
> +@dfn{standard error process}.  This process will have the default

As a general rule, any use of @dfn should have a corresponding @cindex
entry leading to the text.  So please add one here.

> +If you have passed a non-@code{nil} @var{stderr} to
> +@code{make-process}, it will have a standard error process.
> +@xref{Asynchronous Processes}.  In that case, waiting for process
> +output from the main process doesn't wait for output from the standard
> +error process.  To make sure that you have received both standard
> +output and error from a process, use the following code:

Suggest a minor rewording of the last sentence:

  To make sure you have received both all of standard output and all of
  standard error from a process ...

Otherwise, LGTM, thanks.