vim: Visual replace text
This PR makes Vim emulation replicate the behavior of "putting" text while in visual mode. When the user presses "p" with a selected range, the range's content will now be replaced by the contents of the current register, replacing the register's content with the text that was replaced.
Furthermore, this PR also adds the same feature for the system clipboard by using "Ctrl + Shift + v", similar to what is present in insert mode.