patch 8.2.4744: a terminal window can't use the bell

Problem:    A terminal window can't use the bell.
Solution:   Add bell support for the terminal window. (closes #10178)
diff --git a/runtime/doc/options.txt b/runtime/doc/options.txt
index ddd5af0..2ed4a8f 100644
--- a/runtime/doc/options.txt
+++ b/runtime/doc/options.txt
@@ -1265,6 +1265,7 @@
 	separated list of items. For each item that is present, the bell
 	will be silenced. This is most useful to specify specific events in
 	insert mode to be silenced.
+	You can also make it flash by using 'visualbell'.
 
 	item	    meaning when present	~
 	all	    All events.
@@ -1290,6 +1291,7 @@
 	register    Unknown register after <C-R> in |Insert-mode|.
 	shell	    Bell from shell output |:!|.
 	spell	    Error happened on spell suggest.
+	term	    Bell from |:terminal| output.
 	wildmode    More matches in |cmdline-completion| available
 		    (depends on the 'wildmode' setting).