Elide private key in KeyPair Debug impl #1763

Job	Run time
Validate external types appearing in public API	1m 41s
Build rustls-cert-gen as a standalone package	25s
build (macOS-latest, stable)	4m 12s
build-windows	13m 27s
build (ubuntu-latest, stable)	6m 53s
Measure coverage	6m 55s
Format & clippy	6m 28s
build (ubuntu-latest, beta)	7m 0s
build (ubuntu-latest, nightly)	6m 29s
Documentation (stable)	1m 13s
build (ubuntu-latest, stable 7 months ago)	6m 55s
Documentation (nightly)	1m 15s
Check semver compatibility	1m 3s
	1h 3m 56s

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