RFR: 8261366: Add discussion of IEEE 754 to BigDecimal [v2]

[Joe Darcy]

> Informative update to BigDecimal and related classes to latest IEEE 754 terminology, including a discussion of the similarities and differences of BigDecimal and IEEE 754 decimal arithmetic.
> 
> Once the wording is finalized, I'll reflow any modified paragraphs and update the copyright years, etc.

Joe Darcy has updated the pull request incrementally with one additional commit since the last revision:

  Fix typos found in review.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2868/files
  - new: https://git.openjdk.java.net/jdk/pull/2868/files/1ff051bb..a29d60fd

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2868&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2868&range=00-01

  Stats: 4 lines in 1 file changed: 0 ins; 0 del; 4 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2868.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2868/head:pull/2868

PR: https://git.openjdk.java.net/jdk/pull/2868