fix(lsp): ensure buffers are re-attached on rename (#16266)

If a LSP server sent a workspace edit containing a rename the buffers
file name changed without the server receiving a close notification for
the old buffer and without the client properly re-attaching on the new
file.

This affected `Move` code-actions in nvim-jdtls, but also
`vim.lsp.buf.rename` on a class level.

runtime/lua/vim/lsp.lua

@@ -472,7 +472,11 @@ local function text_document_did_open_handler(bufnr, client)
 
   -- Next chance we get, we should re-do the diagnostics
   vim.schedule(function()
-    vim.lsp.diagnostic.redraw(bufnr, client.id)
+    -- Protect against a race where the buffer disappears
+    -- between `did_open_handler` and the scheduled function firing.
+    if vim.api.nvim_buf_is_valid(bufnr) then
+      vim.lsp.diagnostic.redraw(bufnr, client.id)
+    end
   end)
 end