git: openjdk/jdk17: 8271489: (doc) Clarify Filter Factory example

[Roger Riggs]

Changeset: 286d3136
Author:    Roger Riggs <rriggs at openjdk.org>
Date:      2021-07-29 20:22:02 +0000
URL:       https://git.openjdk.java.net/jdk17/commit/286d31363551b00c4b3f50f5ee388f8e7875d0a1

8271489: (doc) Clarify Filter Factory example

Reviewed-by: iris, kcr, naoto, bpb

! src/java.base/share/classes/java/io/ObjectInputFilter.java