TOC generated by asciidoc for core-beans.adoc is truncated

[Farteen]

Affects: 5.2.2.RELEASE

This is a trivial issue with table of contents which are generated by asciidoc. Look at the picture
I uploaded some tocs were missing. Last three days I had been reading the spring-framework-reference with previous RELEASE(maybe 5.1.9RELEASE). When I open the newest reference website, the missing happened.

I've been comparing the diff between previous RELEASE and 5.2.2 RELEASE, something wrong in
core/core-beans.adoc

After I delete the four equal marks which stand for Level 3 Section in asciidoc, and execute
./gradlew asciidoctor
the reference generated in my computer has the complete tocs.

[rstoyanchev]

It looks like there was a mismatched ==== at the end of a code sample and then an unbalanced [NOTE] a couple of paragraphs below, which made both go unnoticed for a while. Then a recent change in 55011e7 fixed the [NOTE] which then exposed the other unbalanced marker.

[sbrannen]

I'm reopening this since the latest build snapshots display improper headings.

https://docs.spring.io/spring/docs/5.2.2.BUILD-SNAPSHOT/spring-framework-reference/core.html#beans-java-bean-annotation