RFR: 8254275: Development to revise ValueBased.html for consistency with inline class migration

[Dan Smith]

Polishing the specification of "value-based class" to align with requirements of inline classes, allow classes (like
Integer) with deprecated constructors, and clarify expectations for clients.

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Commit messages:
 - 8254275: Development to revise ValueBased.html for consistency with inline class migration

Changes: https://git.openjdk.java.net/valhalla/pull/222/files
 Webrev: https://webrevs.openjdk.java.net/?repo=valhalla&pr=222&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8254275
  Stats: 25 lines in 1 file changed: 13 ins; 8 del; 4 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/222.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/222/head:pull/222

PR: https://git.openjdk.java.net/valhalla/pull/222