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)

etc/NEWS

@@ -1066,8 +1066,9 @@ variable for remote shells.  It still defaults to "/bin/sh".
 
 ** Single shell commands
 
-*** 'shell-command-width' defines the number of output columns
-for asynchronous shell command.
+---
+*** 'shell-command-width' defines the number of display columns
+available for output of asynchronous shell commands.
 
 ** Pcomplete
 

lisp/simple.el

@@ -3352,9 +3352,10 @@ is output."
   :version "26.1")
 
 (defcustom shell-command-width nil
-  "Number of columns available for asynchronous shell command output.
+  "Number of display columns available for asynchronous shell command output.
 If nil, use the shell default number (usually 80 columns).
-If a positive integer, use a fixed width for command output."
+If a positive integer, tell the shell to use that number of columns for
+command output."
   :type '(choice (const :tag "Use system limit" nil)
                  (integer :tag "Fixed width" :value 80))
   :group 'shell