Merge remote-tracking branch 'origin/master' into enum-FileIngestionMethod

.github/ISSUE_TEMPLATE.md

.github/ISSUE_TEMPLATE/bug_report.md

.github/ISSUE_TEMPLATE/feature_request.md

.github/workflows/test.yml

.gitignore

.travis.yml

Makefile

Makefile.config.in

README.md

configure.ac

doc/manual/advanced-topics/post-build-hook.xml

doc/manual/command-ref/conf-file.xml

doc/manual/command-ref/env-common.xml

doc/manual/command-ref/nix-env.xml

doc/manual/command-ref/nix-shell.xml

doc/manual/command-ref/nix-store.xml

doc/manual/expressions/advanced-attributes.xml

doc/manual/expressions/builtins.xml

doc/manual/expressions/expression-syntax.xml

doc/manual/expressions/simple-building-testing.xml