prep for 2023. Fixed many bugs. Added pdf guide

vendor/phpoffice/phpspreadsheet/docs/assets/ClassDiagrams/Classes/PHPExcel.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace ClassDiagrams
+{
+    public class PHPExcel
+    {
+        /// <remarks></remarks>
+        public Worksheet Worksheets
+        {
+            get
+            {
+                throw new System.NotImplementedException();
+            }
+            set
+            {
+            }
+        }
+    }
+
+    public class PHPExcel_Writer_PDF : PHPExcel_Writer_IWriter
+    {
+        #region PHPExcel_Writer_IWriter Members
+
+        public PHPExcel writes
+        {
+            get
+            {
+                throw new Exception("The method or operation is not implemented.");
+            }
+            set
+            {
+                throw new Exception("The method or operation is not implemented.");
+            }
+        }
+
+        #endregion
+    }
+}