chore: add docs to readme

[qx-nico]

Description

Link mention to Cosmos EVM docs' page on the main readme of the repository.

https://evm.cosmos.network/

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Author Checklist

All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.

I have...

• tackled an existing issue or discussed with a team member
• left instructions on how to review the changes
• targeted the main branch

Reviewers Checklist

All items are required.
Please add a note if the item is not applicable
and please add your handle next to the items reviewed
if you only reviewed selected items.

I have...

• added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• confirmed all author checklist items have been addressed
• confirmed that this PR does not change production code
• reviewed content
• tested instructions (if applicable)
• confirmed all CI checks have passed