chore: Have rust-analyzer use the stable toolchain

[vezenovm]

Description

Problem*

Today when working inside of Noir I suddenly started getting red all over any functions or structures that used proc macros:

This was littering my code base and was quite annoying as it made it harder to see legitimate errors.

Summary*

According to https://rust-analyzer.github.io/manual.html#toolchain we can force rust-analyzer to use the stable toolchain via an environment variable. So even though our rust toolchain is set to 1.74.1 we should not be out of sync with rust-analyzer updates.

My proc macros errors from rust-analyzer are all gone now.

Additional Context

Documentation*

Check one:

• No documentation needed.
• Documentation included in this PR.
• [For Experimental Features] Documentation to be submitted in a separate PR.

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[github-actions]

Changes to Brillig bytecode sizes

Generated at commit: f87cbc9a44c3068147651f713da61d7217cab8ca, compared to commit: f337992de96ef656681ebfc96a30c2c9c9b82a70

🧾 Summary (10% most significant diffs)

Program	Brillig opcodes (+/-)	%
poseidonsponge_x5_254	-3 ✅	-0.07%

---

Full diff report 👇

Program	Brillig opcodes (+/-)	%
poseidonsponge_x5_254	4,251 (-3)	-0.07%

[github-actions]

Changes to number of Brillig opcodes executed

Generated at commit: f87cbc9a44c3068147651f713da61d7217cab8ca, compared to commit: f337992de96ef656681ebfc96a30c2c9c9b82a70

🧾 Summary (10% most significant diffs)

Program	Brillig opcodes (+/-)	%
poseidonsponge_x5_254	+3 ❌	+0.00%

---

Full diff report 👇

Program	Brillig opcodes (+/-)	%
poseidonsponge_x5_254	183,753 (+3)	+0.00%

[github-actions]

Peak Memory Sample

Program	Peak Memory
keccak256	77.76M
workspace	122.05M
regression_4709	273.24M
ram_blowup_regression	1.60G
private-kernel-tail	204.31M
private-kernel-reset	746.63M
private-kernel-inner	310.59M
parity-root	169.56M

[github-actions]

Compilation Sample

Program	Compilation Time	%
sha256_regression	0m1.444s	3%
regression_4709	0m0.731s	-2%
ram_blowup_regression	0m15.238s	2%
rollup-base-public	3m25.797s	1%
rollup-base-private	3m7.289s	3%
private-kernel-tail	0m1.178s	-6%
private-kernel-reset	0m7.943s	-5%
private-kernel-inner	0m2.559s	8%
parity-root	0m0.938s	13%
noir-contracts	2m35.766s	-9%