fix(executor): Preserve type of visual mode

[notEvil]

Resolves: #375

How to Test

1. select a range with v, V or <c-v>
2. escape
3. select a range with a different type and leave the cursor on either side
4. start legendary and choose a builtin motion (e.g. "Start of next word")
5. assert the type of visual mode and cursor side didn't change

Testing for Regressions

I have tested the following:

• Triggering keymaps from legendary.nvim in all modes (normal, insert, visual)
• Creating keymaps via legendary.nvim, then triggering via the keymap in all modes (normal, insert, visual)
• Triggering commands from legendary.nvim in all modes (normal, insert, visual)
• Creating commands via legendary.nvim, then running the command manually from the command line
• augroup/autocmds created through legendary.nvim work correctly

[mrjones2014]

Also looks like the stylua check is failing.

[mrjones2014]

Thanks for the PR!!