RFR: 8350548: java.lang.classfile package javadoc has errors

[Adam Sotona]

j.l.classfile package-summary contains many code snippets.
Some of the shorter snippets are embedded in the javadoc and therefore are not validated by the tests.
One embedded code snippet contains a typo, and two snippets do not reflect the actual API method name.

This patch fixes the code snippets.

Please review.

Thanks,
Adam

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Commit messages:
 - 8350548: java.lang.classfile package javadoc has errors

Changes: https://git.openjdk.org/jdk/pull/23743/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23743&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8350548
  Stats: 3 lines in 1 file changed: 0 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/23743.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23743/head:pull/23743

PR: https://git.openjdk.org/jdk/pull/23743