Update day-17.md

:req --> :reg ## reference: [1] [View and load macros](https://www.redhat.com/sysadmin/use-vim-macros) > Because macros are saved into Vim registers, you can view saved macros by using the command :reg to see the content of all registers. ## example: ```sh :reg --- Registers --- "" , "h 0r#f"xldf,A,^[p0df,$px:s/,/\t/g^Mj "- , ... ```