Merge branch 'master' into content-standards

docs/basics/skills.md

docs/core/architecture.md

docs/core/hacking.md

docs/documentation.md

docs/extensions/advanced.md

docs/extensions/basics.md

docs/extensions/civix.md

docs/extensions/files.md

docs/extensions/troubleshooting.md

docs/img/check.png

docs/img/danger.png

docs/img/info.png

docs/index.md

docs/js/custom.js

docs/markdownrules.md

mkdocs.yml

redirects/wiki-crmdoc.txt