Move respect accept header on no handler to 6.3.1

This commit moves the changelog entry for the change to respect the
accept header on no handler from the 7.0.0 section of the docs to 6.3.1.

docs/CHANGELOG.asciidoc

@@ -99,6 +99,8 @@ coming[6.3.1]
 
 Reduce the number of object allocations made by {security} when resolving the indices and aliases for a request ({pull}30180[#30180])
 
+Respect accept header on requests with no handler ({pull}30383[#30383])
+
 //[float]
 //=== Regressions
 
@@ -174,10 +176,6 @@ Engine::
 
 Ingest::
 * Don't allow referencing the pattern bank name in the pattern bank {pull}29295[#29295] (issue: {issue}29257[#29257])
-Respect accept header on requests with no handler ({pull}30383[#30383])
-Rollup::
-* Validate timezone in range queries to ensure they match the selected job when
-searching ({pull}30338[#30338])
 
 Java High Level REST Client::
 * Bulk processor#awaitClose to close scheduler {pull}29263[#29263]