Add a few apiNote concerning source-level modifiers that are not represented in java.lang.reflect.Modifier.
------------- Commit messages: - JDK-8322979: Add informative discussion to Modifier Changes: https://git.openjdk.org/jdk/pull/17338/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17338&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8322979 Stats: 27 lines in 1 file changed: 26 ins; 0 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/17338.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/17338/head:pull/17338 PR: https://git.openjdk.org/jdk/pull/17338
