RFR: JDK-8295391: Add discussion of binary <-> decimal conversion issues

[Joe Darcy]

Add discussion of some of the common pitfalls related to decimal <-> binary conversion.

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Commit messages:
 - Appease jcheck.
 - JDK-8295391: Add discussion of binary <-> decimal conversion issues

Changes: https://git.openjdk.org/jdk/pull/16566/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16566&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8295391
  Stats: 133 lines in 1 file changed: 133 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/16566.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16566/head:pull/16566

PR: https://git.openjdk.org/jdk/pull/16566