docs: Update contributing guide

[richardgreg]

• Closes #2326

Summary

Updated contributing guide on how to work with unreleased forc and fuel-core functionality.

Another goal is to document how to turn e2es for devnet on and off

Checklist

• [x] All changes are covered by tests (or not applicable)
• [x] All changes are documented (or not applicable)
• [x] I reviewed the entire PR myself (preferably, on GH UI)
• [x] I described all Breaking Changes (or there's none)

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
ts-api-docs	❌ Failed (Inspect)			Oct 2, 2024 1:35pm
ts-docs	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Oct 2, 2024 1:35pm

1 Skipped Deployment

Name	Status	Preview	Comments	Updated (UTC)
create-fuels-counter-example	⬜️ Ignored (Inspect)			Oct 2, 2024 1:35pm

[vercel[bot]]

@richardgreg is attempting to deploy a commit to the Fuel Labs Team on Vercel.

A member of the Team first needs to authorize it.

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #3202 will improve performances by ×3.4

_{Comparing richardgreg:richardgreg/docs/contributing-giude-update (c11cda6) with master (b869ee8)}

Summary

⚡ 1 improvements ✅ 20 untouched benchmarks

Benchmarks breakdown

	Benchmark	master	richardgreg:richardgreg/docs/contributing-giude-update	Change
⚡	Instantiate from an address	97.3 ms	28.5 ms	×3.4

[petertonysmith94]

Converting this to a draft until all resolved @richardgreg

[richardgreg]

Hi @petertonysmith94, sorry about the delay, had to take care of a personal errand.

I've added the note but noticed the next branch got deleted, which might have automatically closed my PR. Should I reopen against the master branch?