* update nvim version to 0.11.0
* replace deprecated nvim_err_write/nvim_err_writeln call
* replace deprecated func for diagnostic and lsp
* use vim.hl instead
* use new way to define diagnostic signs
By default, when you press `*` to search word under the cursor, the
option `smartcase` is ignored. This means that if you press `*` when
your cursor is on `The`, the lower case one `the` is also searched.
In this commit, we translate star and # search into normal search so that
'smartcase' option is respected.