[doc] The link of Pulsar Functions SDK for Java is 404

[huangdx0726]

Describe the bug
A clear and concise description of what the bug is.

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://pulsar.apache.org/docs/en/functions-overview/'
2. Scroll down to 'Word count example'
3. Click on 'Pulsar Functions SDK for Java'
4. See error

[Jennifer88huang-zz]

@huangdx0726 Thank you very much for your report.

[slominskir]

I think this is fixed now? I cannot reproduce.

[huangdx0726]

It's fixed.