fix: Remove outdated info for headline field

Author: distantnative

content/docs/2_reference/3_panel/3_fields/0_headline/reference-panelfield.txt

@@ -39,28 +39,4 @@ fields:
 
 (field-options: headline)
 
-## Hiding the headline numbers
-
-```yaml
-fields:
-  pageSettings:
-    label: Page Settings
-    type: headline
-    numbered: false
-  type:
-    label: Page type
-    type: text
-  state:
-    label: Draft
-    type: toggle
-  content:
-    label: Content
-    type: headline
-    numbered: false
-  text:
-    label: Text
-    type: textarea
-```
-
-You can also just hide the numbers of one or a few headlines on a page, those headlines are then skipped when counting through. The others will get numbers like normal.