Set MSRV 1.85 & use stable toolchain

[HDauven]

No description provided.

[Copilot]

Pull request overview

This pull request updates the project to use Rust's stable toolchain and sets the Minimum Supported Rust Version (MSRV) to 1.85. The changes align with Rust 1.85's stabilization of elided lifetimes in associated constant contexts, eliminating the need for a nightly toolchain.

Changes:

• Updated toolchain from nightly-2023-11-10 to stable
• Set MSRV to 1.85 in Cargo.toml files
• Updated lifetime elision syntax to use explicit '_ lifetimes
• Removed nightly toolchain requirement from documentation

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
rust-toolchain.toml	Changed toolchain channel from nightly to stable
dusk-merkle/Cargo.toml	Added rust-version = "1.85"
poseidon-merkle/Cargo.toml	Added rust-version = "1.85"
dusk-merkle/src/node.rs	Updated lifetime elision to explicit '_
dusk-merkle/src/tree.rs	Updated lifetime elision to explicit '_ in three functions
dusk-merkle/src/walk.rs	Simplified match expression to if-let statement
dusk-merkle/README.md	Removed nightly toolchain requirement note
rustfmt.toml	Removed wrap_comments configuration

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[HDauven]

Blocked by: dusk-network/plonk#857 dusk-network/Poseidon252#273

[moCello]

LGTM