[NETBEANS‑5838] Support for `{@return …}` Javadoc tag (JDK‑8075778)

### Description

From [NETBEANS‑5838]:

1) Currently
```java
/**
* {@return something}
*/
```
does not show up in the Javadoc window. According to [JDK-8075778][JDK‑8075778] the text in the tag should be displayed in the description (prefixed with "Returns " and in the "returns" section.

2) Also autoformatting the source code currently transforms the tag into
```java
/**
* {
*
* @return something}
*/
```
which is not recognized by the Javadoc generator anymore. The generated output contains "\{" as the description and the given text including "}" (but without the "{") in the "returns" section.

[NETBEANS‑5838]: https://issues.apache.org/jira/browse/NETBEANS-5838
[JDK‑8075778]: https://bugs.openjdk.java.net/browse/JDK-8075778
[JDK‑8256804]: https://bugs.openjdk.org/browse/JDK-8256804

### Use case/motivation

_No response_

### Related issues

- [NETBEANS‑5838]
- [JDK‑8075778]
- [JDK‑8256804] (**CSR**)

### Are you willing to submit a PR?

- [ ] Yes I am willing to submit a PR!

### Code of Conduct

- [X] I agree to follow the Apache Software Foundation's [Code of Conduct](https://www.apache.org/foundation/policies/conduct.html)

Reproduce the examples in the issue in the Javadoc window and with source autoformatting, then trace the Java editor's Javadoc parsing and formatting entry points. Done means {@return …} text appears in the description and returns section, while formatting preserves a valid tag that the Javadoc generator recognizes.

Written by the indexing model from the issue text.