docs: Add link to RAGAS metrics page

[ssbushi]

Checklist (if applicable):

• PR title is following https://www.conventionalcommits.org/en/v1.0.0/
• Tested (manually, unit tested, etc.)
• Docs updated (updated docs or a docs bug required)

[pavelgj]

looking at the page, there are many more metrics listed there... do we want to link to specific metrics instead?
Ex: https://docs.ragas.io/en/stable/concepts/metrics/available_metrics/faithfulness/

[ssbushi]

I thought of that, but RAGAS change their metrics frequently, I was afraid we might have to keep up with them so I used the parent page instead.

I can switch to using specific metrics if you feel that's preferred.

[pavelgj]

if they change the metrics frequently then it means that whatever we have may not be up-to-date, right? what's the point of linking to their docs if it may or may not be accurate?

[ssbushi]

The reason we should link is because they have detailed explanation on how a metric is computed. Some of the feedback we received for evals is a scenario like: 'user expects relevancy to be 1.0 but it is only 0.5, why is that?'

The reason I am hesitant to link to individual docs for each metric is because RAGAS seem to change their metrics collection (either removing them or renaming them). E.g.: ANSWER_RELEVANCY in genkitEvals is now called "Response Relevancy" in RAGAS.

Catching up to RAGAS is a different problem altogether.

You are right though... taking them to a top level directory does not guarantee that the metric details would be available. The way I see it, both approaches have their cons.

[chrisraygill]

Alternatively, should we just bring the explanations of the metrics into our docs so we don't need to link our to RAGAS docs?

I believe our metrics are already just "RAGAS-inspired", so it's okay if we deviate as long as we explain what they mean well.

[ssbushi]

That makes sense to me... but there's going to be more metrics in this plugin and we should move that into it's own documentation?

How about including a summary in the JSDoc for these metrics and linking to the JS API ref?