Problem:
- The :Evaluate result window is not cleaned up when the cursor moves.
- This window is not focusable.
Solution:
Replace the old implementation from autozimu/LanguageClient-neovim with
vim.lsp.util.open_floating_preview and implement custom focusing logic.
Also remove g:termdebug_useFloatingHover option now that it's working
correctly.
cd1b14f027
