RFR: 8367787: Expand use of representation equivalence terminology in Float16

[Joe Darcy]

Analogous to recent updates made in Float and Double, along with a double -> Float16 typo fix.

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Commit messages:
 - JDK-8367787: Expand use of representation equivalence terminology in Float16

Changes: https://git.openjdk.org/jdk/pull/27322/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27322&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367787
  Stats: 10 lines in 1 file changed: 9 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/27322.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27322/head:pull/27322

PR: https://git.openjdk.org/jdk/pull/27322