RFR: 8325073: javadoc warnings: missing @param tags and other issues [v2]

[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
> 
> This PR does not need a CSR: most of the changes are clarifications or documenting of missing parameters.

Andy Goryachev has updated the pull request incrementally with one additional commit since the last revision:

  review comments

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

Changes:
  - all: https://git.openjdk.org/jfx/pull/1384/files
  - new: https://git.openjdk.org/jfx/pull/1384/files/bdc3c5bd..7fb2715a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=1384&range=01
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=1384&range=00-01

  Stats: 6 lines in 6 files changed: 0 ins; 0 del; 6 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