docs(changelog): fix incorrect documentation title

Change-Id: Idb4b174f65891ba406f83c213c80ebb8a6ba0b81
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/changelog.yaml b/changelog.yaml
index d3e235d..d2dc992 100644
--- a/changelog.yaml
+++ b/changelog.yaml
@@ -31,7 +31,7 @@
     type: ci
     hidden: true
 
-  - title: Build System
+  - title: Documentation
     description: Documentation-only changes
     type: docs
     hidden: true