Merge remote-tracking branch 'origin/master' into cross-jobs

.github/STALE-BOT.md

.github/workflows/test.yml

.gitignore

Makefile

Makefile.config.in

README.md

config/config.guess

config/config.sub

configure.ac

doc/manual/local.mk

doc/manual/src/advanced-topics/cores-vs-jobs.md

doc/manual/src/command-ref/env-common.md

doc/manual/src/command-ref/nix-build.md

doc/manual/src/command-ref/nix-channel.md

doc/manual/src/command-ref/nix-copy-closure.md

doc/manual/src/command-ref/nix-env.md

doc/manual/src/command-ref/nix-hash.md

doc/manual/src/command-ref/nix-instantiate.md

doc/manual/src/command-ref/nix-prefetch-url.md

doc/manual/src/command-ref/nix-shell.md