vim: Fix Y on last line (#2975)

For zed-industries/community#2044

Release Notes:

- vim: Fix y in VISUAL LINE mode when last line has no trailing newline
([#2044](https://github.com/zed-industries/community/issues/2044)).

assets/keymaps/vim.json

@@ -455,6 +455,7 @@
       "shift-d": "vim::VisualDelete",
       "shift-x": "vim::VisualDelete",
       "y": "vim::VisualYank",
+      "shift-y": "vim::VisualYank",
       "p": "vim::Paste",
       "shift-p": [
         "vim::Paste",