Update #4455, Regenerate all commands' docs (#4557)

docs/commands/update.md

@@ -22,6 +22,11 @@ Update a column value
 > echo {'name': 'nu', 'stars': 5} | update name 'Nushell'
 ```
 
+Use in block form for more involved updating logic
+```shell
+> echo [[count fruit]; [1 'apple']] | update count {|f| $f.count + 1}
+```
+
 Use in block form for more involved updating logic
 ```shell
 > echo [[project, authors]; ['nu', ['Andrés', 'JT', 'Yehuda']]] | update authors { get authors | str collect ',' }