Update docs/classic-ui/theming/diazo.md

Co-authored-by: Copilot <[email protected]>

Author: thet

docs/classic-ui/theming/diazo.md

@@ -202,7 +202,7 @@ One way is to select another theme and then switch back to your own theme in the
 For a programmatic way, check [this pull request in plonetheme.barceloneta](https://github.com/plone/plonetheme.barceloneta/pull/404).
 
 
-### Completly disable Diazo
+### Completely disable Diazo
 
 You might want to not use Diazo for your theme and fully disable it.
 This can be done by setting the `X-Theme-Disabled` http header before Diazo gets active, e.g. in a `IBeforeTraverseEvent` event subscriber.