Update Rust toolchain to 1.85.0

[Rigidity]

To resolve cargo-machete installation errors due to the new 2024 Rust edition. I don't think we need to use the 2024 edition ourselves yet, since this unnecessarily increases the MSRV (minimum supported Rust version) of chia_rs beyond what it needs to be. But once we decide the time is right we can do so.

[coveralls-official]

Pull Request Test Coverage Report for Build 13535310289

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 84.313%

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Totals
Change from base Build 13535027260:	0.0%
Covered Lines:	13576
Relevant Lines:	16102

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💛 - Coveralls