gopls/doc: update neovim examples for nvim 0.7

On neovim 0.7-dev `apply_workspace_edit` needs the encoding.

This PR updates the organize imports documentation example.

This does not break neovim v0.6+. Haven't tested in <=v0.5.

refs https://github.com/neovim/neovim/issues/14090

Change-Id: I82a08c54dd94e6aacb5aa30a19a1fa209ef5264b
GitHub-Last-Rev: f4072a0eec9c14a0efd618c1835e0d99c4a2d6f4
GitHub-Pull-Request: golang/tools#375
Reviewed-on: https://go-review.googlesource.com/c/tools/+/390417
Reviewed-by: Robert Findley <rfindley@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
diff --git a/gopls/doc/vim.md b/gopls/doc/vim.md
index 887a246..d9b33ac 100644
--- a/gopls/doc/vim.md
+++ b/gopls/doc/vim.md
@@ -182,7 +182,7 @@
     for _, res in pairs(result or {}) do
       for _, r in pairs(res.result or {}) do
         if r.edit then
-          vim.lsp.util.apply_workspace_edit(r.edit)
+          vim.lsp.util.apply_workspace_edit(r.edit, "UTF-8")
         else
           vim.lsp.buf.execute_command(r.command)
         end