feat: use jobstart instead of termopen (deprecated) in Neovim 0.11

```vim
DEPRECATED IN 0.11					*deprecated-0.11*

VIMSCRIPT
• *termopen()* Use |jobstart() with `{term: v:true}`.
```

use jobstart instead of termopen in `kitty_commands.lua`

from
```lua
  local success, error = pcall(vim.fn.termopen, full_cmd, {
```
to
```lua
  local success, error = pcall(vim.fn.jobstart, full_cmd, {
    term = true,
```