RFR: JDK-8252075: Documentation error in LayoutManager2 interface

[Renjith Kannath Pariyangad]

Updated the documentation with proper meaningful message for better understanding.

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Commit messages:
 - JDK-8252075 : Documentation error in LayoutManager2 interface

Changes: https://git.openjdk.org/jdk/pull/10549/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10549&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8252075
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/10549.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10549/head:pull/10549

PR: https://git.openjdk.org/jdk/pull/10549