As indicated in [JDK-8233338](https://bugs.openjdk.java.net/browse/JDK-8233338), this fixes all of our javadoc HTML headings to conform with the rule that all HTML heading tags in class documents must start with `<h2>` and be nested correctly (i.e., no skipping levels). See [JDK-8219801](https://bugs.openjdk.java.net/browse/JDK-8219801) and [JDK-8220379](https://bugs.openjdk.java.net/browse/JDK-8220379).
We have a few places where we are using `<h1>` tags and several more where we are using `<h3>`. As a result, the build of FX docs via `gradle javadoc` fails with JDK 13. We had one `<h4>` heading that wasn't supposed to be nested with the previous `<h3>` heading, so I made both of the `<h2>` to reflect this. This fix can go in at any time, but must be done before we can switch the boot JDK to 13 in [JDK-8232064](https://bugs.openjdk.java.net/browse/JDK-8232064), else the build will fail. ---------------- Commits: - c5d8372a: 8233338: FX javadoc headings are out of sequence Changes: https://git.openjdk.java.net/jfx/pull/29/files Webrev: https://webrevs.openjdk.java.net/jfx/29/webrev.00 Issue: https://bugs.openjdk.java.net/browse/JDK-8233338 Stats: 69 lines in 26 files changed: 0 ins; 0 del; 69 mod Patch: https://git.openjdk.java.net/jfx/pull/29.diff Fetch: git fetch https://git.openjdk.java.net/jfx pull/29/head:pull/29 PR: https://git.openjdk.java.net/jfx/pull/29
