Update story header flag translation and docu

DOCUMENTATION.md

@@ -400,6 +400,7 @@ Pages work the same as always in WordPress, just with some additional fields and
 | Short Name | String | Shortened name of the page required for custom tabs in stories.
 | Filter & Search ID | String | Custom identifier to be used with plugin. Does nothing on its own.
 | Story ID | String | ID of a story post. Only used by the "Story Page/Mirror" page templates.
+| Show story header | Check | Renders the story header for the given story ID. "Story Page" template only.
 
 ## Shared Options
 

includes/functions/_setup-meta-fields.php

@@ -3157,12 +3157,12 @@ function fictioneer_render_extra_metabox( $post ) {
       );
     }
 
-    // Checkbox: Show story template header
+    // Checkbox: Show story header
     if ( current_user_can( 'manage_options' ) ) {
       $output['fictioneer_template_show_story_header'] = fictioneer_get_metabox_checkbox(
         $post,
         'fictioneer_template_show_story_header',
-        __( 'Show story template header', 'fictioneer' )
+        __( 'Show story header', 'fictioneer' )
       );
     }
   }