Merge #15440 close 'shell' :terminal automatically

runtime/doc/news.txt

@@ -190,6 +190,10 @@ The following changes to existing APIs or features add new behavior.
   supports it, unless |'keywordprg'| was customized before calling
   |vim.lsp.start()|.
 
+• Terminal buffers started with no arguments (and use 'shell') close
+  automatically if the job exited without error, eliminating the (often
+  unwanted) "[Process exited 0]" message.
+
 ==============================================================================
 REMOVED FEATURES                                                 *news-removed*
 

runtime/doc/various.txt

@@ -249,6 +249,10 @@ gx			Opens the current filepath or URL (decided by
 			Fails if changes have been made to the current buffer,
 			unless 'hidden' is set.
 
+			If {cmd} is omitted, and the 'shell' job exits with no
+			error, the buffer is closed automatically
+			|default-autocmds|.
+
 			To enter |Terminal-mode| automatically: >
 			      autocmd TermOpen * startinsert
 <

runtime/doc/vim_diff.txt

@@ -133,6 +133,8 @@ remove them and ":autocmd {group}" to see how they're defined.
 
 nvim_terminal:
 - BufReadCmd: Treats "term://" buffers as |terminal| buffers. |terminal-start|
+- TermClose: A |terminal| buffer started with no arguments (which thus uses
+  'shell') and which exits with no error is closed automatically.
 
 nvim_cmdwin:
 - CmdwinEnter: Limits syntax sync to maxlines=1 in the |cmdwin|.