GitLab

This has never worked and caused issues such as Bug#30460.

* src/process.c (Fmake_process): Don't accept :stop key any more.
(syms_of_process): Define needed symbol 'null'.

* test/src/process-tests.el (make-process/stop): New unit test.

* doc/lispref/processes.texi (Asynchronous Processes): Remove :stop
key from manual.