vim: Add ctrl-y/e in insert mode (#36017)

Closes #17292

Release Notes:

- vim: Added ctrl-y/ctrl-e in insert mode to copy the next character
from the line above or below

crates/vim/test_data/test_insert_ctrl_y.json

@@ -0,0 +1,5 @@
+{"Put":{"state":"hello\nˇ\nworld"}}
+{"Key":"i"}
+{"Key":"ctrl-y"}
+{"Key":"ctrl-e"}
+{"Get":{"state":"hello\nhoˇ\nworld","mode":"Insert"}}