Add icons to dev-environments

[0xlukem]

📝 Description

This PR adds the icons for remix and hardhat in dev-environments

This PR needs to be merged with this one: papermoonio/polkadot-mkdocs#175

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• ✅ I have time to handle formatting/style feedback myself
• ⚡ Docs team handles formatting (check "Allow edits from maintainers")

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✅ Checklist

• Changes tested
• PaperMoon Style Guide followed

[Copilot]

Pull Request Overview

This PR adds custom icons to the Remix IDE and Hardhat entries in the dev-environments navigation file to improve visual identification of these development tools.

• Adds :custom-remix: icon to Remix IDE navigation entry
• Adds :custom-hardhat: icon to Hardhat navigation entry

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[eshaben]

@0xlukem merge conflicts.

But will wait to merge this til the mkdocs PR is ready too

[nhussein11]

It took me a while to realize that papermoonio/polkadot-mkdocs#175 exists haha. Thanks, @0xlukem; it looks beautiful. Out of curiosity (and not something important), is there an icon we could use for the "local dev node" so that all the pages in the dev environment section have an icon? Or is it okay to leave it blank?

[nhussein11]

many thanks!! 🙏

[eshaben]

@0xlukem the build is failing because it's checking for these icons in the main mkdocs branch. So can you please create a PR to add the icons there too?