[dotnet] Add nullability annotations to print types

dotnet/src/webdriver/ISupportsPrint.cs

@@ -31,9 +31,9 @@ public interface ISupportsPrint
         /// <summary>
         /// Gets a <see cref="PrintDocument"/> object representing a PDF-formatted print representation of the page.
         /// </summary>
-        /// <param name="printOptions">A <see cref="PrintOptions"/> object describing the options of the printed document.</param>
+        /// <param name="options">A <see cref="PrintOptions"/> object describing the options of the printed document.</param>
         /// <returns>The <see cref="PrintDocument"/> object containing the PDF-formatted print representation of the page.</returns>
-        /// <exception cref="ArgumentNullException">If <paramref name="printOptions"/> is <see langword="null"/>.</exception>
-        PrintDocument Print(PrintOptions printOptions);
+        /// <exception cref="ArgumentNullException">If <paramref name="options"/> is <see langword="null"/>.</exception>
+        PrintDocument Print(PrintOptions options);
     }
 }

dotnet/src/webdriver/WebDriver.cs

@@ -378,6 +378,7 @@ public PrintDocument Print(PrintOptions printOptions)
         {
             if (printOptions is null)
             {
+                // TODO the interface names this parameter 'options', but we will be throwing for 'printOptions'. Confusion for users?
                 throw new ArgumentNullException(nameof(printOptions));
             }