docs(index): explain who these docs are for

[HonkingGoose]

Changes

• Explain to incoming readers:
  • That the main Renovate docs are meant for the Renovate Open Source CLI, and the Mend-hosted GitHub App
  • Where to find the correct docs for each Renovate variant
  • If you use a variant, read the variant docs first, then come back and read the main docs, as many concepts/ideas/features/config/etc applies to variants too

Context

A user followed the correct steps, from the wrong docs. When Renovate errored out, the user asked for help, and got pointed to the correct docs:

• renovate/renovate:37-full seems to ignore #29844

I hope to prevent such confusion by clearly stating on the homepage if the user is in the right place, or not.

Location of new content to be decided together

I can't really find a good place (on the current homepage) to put the new info.

The current homepage is mostly marketing/selling the Renovate tool. So putting a boring section about "Am I reading the right docs" will always look bad, no matter where I put it.

We really need to focus the homepage (and readme)

Again, I'm hitting the problem that the homepage tries too much at once. Focusing the homepage (and repo readme) will make it easier for me to put new content in, and have it look good.

I created this issue, which is waiting for an official go/no-go from @rarkins as the Mend team are still deciding on the correct todos:

• Declutter readme #29446

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[HonkingGoose]

Can a Mend maintainer suggest the right links to the Mend-only docs?