RFR: 8283779: Clarify API documentation of NetworkInterface with respect to configuration changes [v3]

[Daniel Fuchs]

> Please find here a change that adds a few `@apiNote` and `@implNote` to `NetworkInterface` to clarify user expectation and implementation.

Daniel Fuchs has updated the pull request incrementally with one additional commit since the last revision:

  Improve class level description again

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20822/files
  - new: https://git.openjdk.org/jdk/pull/20822/files/5ce21bcb..74e32e0b

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20822&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20822&range=01-02

  Stats: 11 lines in 1 file changed: 2 ins; 2 del; 7 mod
  Patch: https://git.openjdk.org/jdk/pull/20822.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20822/head:pull/20822

PR: https://git.openjdk.org/jdk/pull/20822