DOCS-15762 fixes issue in substrCP output (#2362)

Author: jmd-mongo

source/reference/operator/aggregation/substrCP.txt

@@ -90,7 +90,7 @@ Definition
         - ``"cafét"``
 
       * - ``{ $substrCP: [ "cafétéria", 5, 4 ] }``
-        - ``"tér"``
+        - ``"éria"``
 
       * - ``{ $substrCP: [ "cafétéria", 7, 3 ] }``
         - ``"ia"``