[SPARK-3359][DOCS] Fix greater-than symbols in Javadoc to allow building with Java 8

## What changes were proposed in this pull request?

The API documentation build was failing when using Java 8 due to incorrect character `>` in Javadoc.

Replace `>` with literals in Javadoc to allow the build to pass.

## How was this patch tested?

Documentation was built and inspected manually to ensure it still displays correctly in the browser

```
cd docs && jekyll serve
```

Author: Michal Senkyr <mike.senkyr@gmail.com>

Closes #16201 from michalsenkyr/javadoc8-gt-fix.