Rename jacobian_adjustment argument to jacobian

[jgabry]

Submission Checklist

• Run unit tests
• Declare copyright holder and agree to license (see below)

Summary

Closes #877

Deprecates argument jacobian_adjustment in favor of jacobian to be consistent with optimize and laplace. Based on feedback from @avehtari. This affects log_prob, grad_log_prob and hessian.

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Columbia University

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[jgabry]

Making this PR against the prep-v0.7.0 branch to include it in next release

[jgabry]

@andrjohns Are you ok with me changing the name for this argument in the methods you added?