Rename header from 'sumArray' to 'sumForEach'

Author: dimitri-koenig

docs/guides/examples/aggregate_function_combinators/sumForEach.md

@@ -6,7 +6,7 @@ keywords: ['sum', 'array', 'combinator', 'examples', 'sumArray']
 sidebar_label: 'sumArray'
 ---
 
-# sumArray {#sumforeach}
+# sumForEach {#sumforeach}
 
 ## Description {#description}