Fix PR#20345 header name (#8593)

Author: daniel-beck

content/_data/changelogs/weekly.yml

@@ -28819,7 +28819,7 @@
         pr_title: Add CSP-compliant variant of undocumented validateButton 
           script feature
         message: |-
-           Add <code>XJenkinsValidateButtonCallback</code> (a JSON object with <code>callback</code> and <code>arguments</code> keys) as a replacement for the CSP incompatible <code>script</code> HTTP response header for <code>f:validateButton</code>.
+           Add <code>X-Jenkins-ValidateButton-Callback</code> (a JSON object with <code>callback</code> and <code>arguments</code> keys) as a replacement for the CSP incompatible <code>script</code> HTTP response header for <code>f:validateButton</code>.
 
   # pull: 11147 (PR title: Update the ReadMe)
   # pull: 11291 (PR title: Adapt docs for Jira migration)