Integrate 3.8.6 into 4.0.0-dev #427

Job	Run time
Check	15s
Check	15s
Test Suite (ubuntu-latest, MSRV)	33s
Test Suite (ubuntu-latest, MSRV)	33s
Test Suite (ubuntu-latest, stable)	30s
Test Suite (ubuntu-latest, stable)	30s
Coverage	39s
Coverage	39s
Test Suite (macos-latest, MSRV)	1m 5s
Test Suite (macos-latest, MSRV)	7m 14s
Test Suite (macos-latest, stable)	59s
Test Suite (macos-latest, stable)	59s
Test Suite (windows-latest, MSRV)	19s
Test Suite (windows-latest, MSRV)	19s
Lints	51s
Lints	51s
Test Suite (windows-latest, stable)	1s
Test Suite (windows-latest, stable)	1s
no-std build (aarch64-unknown-none)	21s
no-std build (aarch64-unknown-none)	21s
no-std build (thumbv6m-none-eabi)	21s
no-std build (thumbv6m-none-eabi)	21s
Release	0s
Release	0s
	17m 57s

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