doc: telescope no longer supports lsp_code_actions

Telescope removed support for `code_actions`.
See: `help telescope.changelog-1866`

Ref: nvim-telescope/telescope.nvim#1866

Co-authored-by: Lewis Russell <lewis6991@gmail.com>

README.md

@@ -301,7 +301,6 @@ null_ls.setup {
 ```
 
 Will enable `:lua vim.lsp.buf.code_action()` to retrieve code actions from Gitsigns.
-Alternatively if you have [telescope.nvim](https://github.com/nvim-telescope/telescope.nvim) installed, you can use `:Telescope lsp_code_actions`.
 
 ### [trouble.nvim](https://github.com/folke/trouble.nvim)