RFR: 8332103: since-checker - Add missing @ since tags to java.desktop [v4]

[Nizar Benalla]

> If you're currently reviewing this PR, thank you!
> Most fixes here are according to the reports by the since checker tool in #18934 and are pretty simple.
> 
> To make reviewing easier
> - `BasicSliderUI` has the constructor `public BasicSliderUI(JSlider b)` for a long time so the default constructor (without parameters) didn't exist until JDK 16
> 
> For the `package-info` files, it is pretty hard to find source code of JDK 1-5 so I used the `grep` command to find the oldest instance of an `@since` in those packages.
> 
> I found instances of `@since 1.1` in the other packages but `javax/swing/plaf/synth/package-info.java` might be worth checking as most classes there had no `@since`.

Nizar Benalla has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains four commits:

 - Merge remote-tracking branch 'upstream/master' into JDK-8332103
   
   # Conflicts:
   #	src/java.desktop/share/classes/javax/swing/plaf/basic/BasicSliderUI.java
 - See if an empty commit removes sponsor label
 - Swing was added in JDK 1.2
 - Add `@since` tags to `java.desktop`

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Changes: https://git.openjdk.org/jdk/pull/19192/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=19192&range=03
  Stats: 42 lines in 9 files changed: 34 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/19192.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/19192/head:pull/19192

PR: https://git.openjdk.org/jdk/pull/19192