[DOC] Sources documentation missing file reference

[timyig]

What do you want to do?

• Request a change to existing documentation
• Add new documentation
• Report a technical problem with the documentation
• Other

Tell us about your request. Provide a summary of the request.
Here
the file source is mentioned but there is no reference on the sources page:
https://opensearch.org/docs/latest/data-prepper/pipelines/configuration/sources/sources/

On the sources page the random source is also not mentioned.

Version: List the OpenSearch version to which this issue applies, e.g. 2.14, 2.12--2.14, or all.

What other resources are available? Provide links to related issues, POCs, steps for testing, etc.