vim-patch:9.1.0154: shm=F not respected when reloading buffer with 'autoread'

Problem:  shm=F not respected when reloading buffer with 'autoread'
Solution: Check SHM_FILEINFO in buf_check_timestamp()
          (Shougo Matsushita)

closes: vim/vim#14144

9db39b0ec9

Co-authored-by: Shougo Matsushita <Shougo.Matsu@gmail.com>

src/nvim/options.lua

@@ -7331,7 +7331,8 @@ return {
         	items, for instance "scanning tags"
           q	do not show "recording @a" when recording a macro	*shm-q*
           F	don't give the file info when editing a file, like	*shm-F*
-        	`:silent` was used for the command
+        	`:silent` was used for the command; note that this also
+        	affects messages from 'autoread' reloading
           S	do not show search count message when searching, e.g.	*shm-S*
         	"[1/5]"