[DOCS] Fix a PR ID in the changelog (#914)

Author: oliverklee

CHANGELOG.md

@@ -21,7 +21,7 @@ Please also have a look at our
 
 ### Changed
 
-- Mark parsing-related methods of most CSS elements as `@internal` (#907)
+- Mark parsing-related methods of most CSS elements as `@internal` (#908)
 - Mark `OutputFormat::nextLevel()` as `@internal` (#901)
 - Only allow `string` for some `OutputFormat` properties (#885)
 - Make all non-private properties `@internal` (#886)