Fix typo (#16656)

### What does it do?
Fix a lexicon typo

core/lexicon/en/setting.inc.php

@@ -223,7 +223,7 @@
 $_lang['manager_datetime_empty_value_desc'] = 'The text (if any) that will show in grids and forms when a datetime field’s value has not been set. (Default: “–” [a single en dash])';
 
 $_lang['manager_datetime_separator'] = 'Datetime Separator';
-$_lang['manager_datetime_separator_desc'] = 'When the date and time are shown as a combined element, these characters will be used to visually seapate them. (Default: “, ” [comma and space])';
+$_lang['manager_datetime_separator_desc'] = 'When the date and time are shown as a combined element, these characters will be used to visually separate them. (Default: “, ” [comma and space])';
 
 $_lang['setting_debug'] = 'Debug';
 $_lang['setting_debug_desc'] = 'Controls turning debugging on/off in MODX and/or sets the PHP error_reporting level. \'\' = use current error_reporting, \'0\' = false (error_reporting = 0), \'1\' = true (error_reporting = -1), or any valid error_reporting value (as an integer).';