Issue #3051889 by idebr, joachim: $sandbox['max'] count in docs for hook_update_N() is incorrect

(cherry picked from commit d948f9cb)

core/lib/Drupal/Core/Extension/module.api.php

@@ -637,7 +637,7 @@ function hook_update_N(&$sandbox) {
     // This must be the first run. Initialize the sandbox.
     $sandbox['progress'] = 0;
     $sandbox['current_pk'] = 0;
-    $sandbox['max'] = Database::getConnection()->query('SELECT COUNT(myprimarykey) FROM {mytable1}')->fetchField() - 1;
+    $sandbox['max'] = Database::getConnection()->query('SELECT COUNT(myprimarykey) FROM {mytable1}')->fetchField();
   }
 
   // Update in chunks of 20.