nu: Copy basic sh aliases

Held back a little by the issue that you can't really set aliases
conditionally (yet?) in nushell, which is kind of fundamental to my
zsh/sh alias setup. If a program exists, we add some nice aliases -- if
not, we simply degrade gracefully and don't add anything.

PR to track issue:
https://github.com/nushell/nushell/issues/5068

sh/.config/sh/alias

@@ -8,7 +8,10 @@ exist() { type "$1" >/dev/null 2>&1; }
 unalias -a
 
 if alias v >/dev/null 2>&1; then
-	if exist vim; then
+	if exist nvim; then
+	    alias v="nvim"
+		alias vim="vi"
+	elif exist vim; then
 		alias v="vim"
 	else
 		alias v="vi"