RFR: 8325073: javadoc warnings: missing @param tags and other issues

[Andy Goryachev]

This change brings the number of javadoc warnings back to 91 (to be fixed in [JDK-8270996](https://bugs.openjdk.org/browse/JDK-8270996))

- adds missing information in `@param` tags
 - adds `@SuppressWarnings("doclint:missing")` to `Skinnable` to silence the warning due to [JDK-8325071](https://bugs.openjdk.org/browse/JDK-8325071)
 - fixed an empty `<p>` in `Subscription`
 - cleaned up unnecessary `@throws` in Filtered/SortedList

Q: Does this PR need a CSR?

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Commit messages:
 - cleanup
 - 8325073: javadoc warnings: missing @param tags and other issues

Changes: https://git.openjdk.org/jfx/pull/1384/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1384&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325073
  Stats: 203 lines in 68 files changed: 108 ins; 9 del; 86 mod
  Patch: https://git.openjdk.org/jfx/pull/1384.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1384/head:pull/1384

PR: https://git.openjdk.org/jfx/pull/1384