Remove nightly toolchain flag from recommended precommit

[mehmetefeumit]

I asked Claude to give me bash code to select between nix and non-nix environments. So this PR in its entirety was written with AI... UNTIL there was an edit based on spacebear's recommendation below, and the change turned from adding a branching logic to account for the nix shell, to just removing the toolchain flag.

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Please confirm the following before requesting review:

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  AI
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• I have read CONTRIBUTING.md and rebased my branch to produce hygienic commits.

Originally, this PR was for adding an if-statement to the recommended pre-commit hook so that it does not attempt to find +nightly for rust formatter. However, as spacebear mentions below, we do not need it anymore as it is enforced. So this change simply removes that flag now.

[coveralls]

Pull Request Test Coverage Report for Build 20121565157

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 83.176%

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Totals
Change from base Build 20109603088:	0.0%
Covered Lines:	9665
Relevant Lines:	11620

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💛 - Coveralls

[benalleng]

I am hesitant to have two diverging paths for the pre-commit hook. perhaps now with the ohttp-relay in the monorepo we can just encourage the use of the nix dev env such that the pre-commit must be done within the nix shell?

[spacebear21]

I don't think we actually need +nightly in the pre-commit hook anymore, since the toolchain is now enforced in rust-toolchain.toml.

[benalleng]

Ack aa787f1 It would be nice in a followup to address the test step now requiring you to first enter the nix dev shell with the ohttp-relay integration tests.

[nothingmuch]

utACK