Support completionItem/resolve for additional text edits

Author: Steve Poulton

lua/completion.lua

@@ -114,6 +114,15 @@ local function applyAddtionalTextEdits(completed_item)
           item.additionalTextEdits
         )
         vim.lsp.util.apply_text_edits(edits, bufnr)
+      else
+        vim.lsp.buf_request(bufnr, "completionItem/resolve", item, function(err, _, result)
+          if err or not result then
+            return
+          end
+          if result.additionalTextEdits then
+            vim.lsp.util.apply_text_edits(result.additionalTextEdits, bufnr)
+          end
+        end)
       end
     end
   end