Improve documentation of a recent commit

* etc/NEWS: Fix the description of 'shell-command-width'.
Mark the entry as not needing the manual update.

* lisp/simple.el (shell-command-width): Doc fix.  (Bug#35055)
1 job for master in 50 minutes and 5 seconds (queued for 2 seconds)
Status Job ID Name Coverage
failed #1350


Name Stage Failure
test-all Test
Makefile:313: recipe for target 'check-doit' failed
make[2]: *** [check-doit] Error 1
make[2]: Leaving directory '/builds/emacs/emacs/test'
Makefile:288: recipe for target 'check-expensive' failed
make[1]: *** [check-expensive] Error 2
make[1]: Leaving directory '/builds/emacs/emacs/test'
make: *** [check-expensive] Error 2
Makefile:962: recipe for target 'check-expensive' failed
ERROR: Job failed: exit code 1