--watch prints messages to stdout, but should print to stderr

### Version v22.12.0 ### Platform ```text macOS (but reading the source code of Node.js the issue should be present on any platform) ``` ### Subsystem node/lib/internal/main/watch_mode.js ### What steps will reproduce the bug? ``` echo 'process.stdin.resume()' >index.mjs node --watch index.mjs 2>/dev/null ``` In another terminal: ``` touch index.mjs ``` ### How often does it reproduce? Is there a required condition? Always. ### What is the expected behavior? Why is that the expected behavior? Nothing is printed, since I redirect stderr to `/dev/null`. ### What do you see instead? `Restarting 'index.mjs'` is printed (to stdout). ### Additional information How to use stdout and stderr is purely conventional, but the [GNU C library](https://www.gnu.org/software/libc/manual/html_node/Standard-Streams.html) says: > stdout: The standard output stream, which is used for normal output from the program. > > stderr: The standard error stream, which is used for error messages and diagnostics issued by the program. I’m making a program that reads input from stdin and writes to stdout. It is a long-lived program: Another program writes to stdin over time, and consumes output from stdout. I use `--watch` so I can iterate on the sub-program more easily. Unfortunately, `--watch` writes messages to stdout, causing the consuming program to receive output it does not expect. I would argue that my program creates the “normal output” while the `--watch` messages are “diagnostics”. Here’s one of the places where stdout is used instead of stderr: https://github.com/nodejs/node/blob/9400eae52ee10f25d63c06c52479c033e3149580/lib/internal/main/watch_mode.js#L139 Is there a reason for this? Should it be changed to stderr?