RFR: 8312491: Update Classfile API snippets and examples [v11]

[Adam Sotona]

> This pull request updates Classfile API snippets and examples and adds missing javadoc.
> 
> Please review.
> 
> Thanks,
> Adam

Adam Sotona has updated the pull request incrementally with one additional commit since the last revision:

  added notes to attributes

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/14968/files
  - new: https://git.openjdk.org/jdk/pull/14968/files/f4f74cac..ac8709c5

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=14968&range=10
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=14968&range=09-10

  Stats: 135 lines in 37 files changed: 132 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/14968.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14968/head:pull/14968

PR: https://git.openjdk.org/jdk/pull/14968