fix: codelens.enable() nil error and GoListImports crash on empty result

[kanard38]

Two independent bug fixes for Neovim 0.11.x compatibility and a spurious error in GoListImports.

Bug 1: BufWritePre error — attempt to call field 'enable' (a nil value)

When lsp_codelens = true, saving any .go file triggers:

Error executing lua callback: ...go/codelens.lua:59: attempt to call field 'enable' (a nil value)

vim.lsp.codelens.enable() does not exist in Neovim 0.11.x.
The available API is: refresh, clear, run, get, display, save.

Commit c8a356b introduced this regression by replacing the working:

vim.lsp.codelens.refresh({ bufnr = 0 })

with:

vim.lsp.codelens.enable(true, { bufnr = 0 })

This PR reverts to the working refresh() call.

Bug 2: GoListImports spurious error on files with no imports

When gopls returns an empty import list, the code fell through to vim.lsp.util.open_floating_preview() with height = 0, producing a spurious error. An early return with an INFO notification is added instead.

---

Changes

File	Change
lua/go/codelens.lua	Replace vim.lsp.codelens.enable() with vim.lsp.codelens.refresh({ bufnr = 0 })
lua/go/commands.lua	Guard GoListImports against empty result before opening floating preview

---

Reproduction Steps

Bug 1: Set lsp_codelens = true, open any .go file, save it → error fires on BufWritePre:

Error executing lua callback: ...go/codelens.lua:59: attempt to call field 'enable' (a nil value)

Bug 2: Run :GoListImports on a file with no imports → spurious floating window error.

[ray-x]

Thanks!

[Kazuto]

This fix has somehow been overwritten again in commit 7542616, breaking codelense again. Had to pin it to commit 223500c to fix it otherwise the plugin is unusable on neovim 0.11.*

[ray-x]

A release tag for nvim 0.11 is available: v0.11. Alternatively, you might use something like this in your config for old versions:

      vim.lsp.codelens.enable = function(...)
        vim.lsp.codelens.refresh(...)
      end