Rollup merge of #76515 - jumbatm:issue76496-reproducibility-regression, r=oli-obk
Rollup merge of #76515 - jumbatm:issue76496-reproducibility-regression, r=oli-obk

SessionDiagnostic: Fix non-determinism in generated format string.

Fixes #76496.

r? @oli-obk

aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust