Merge pull request #459 from Magento/develop

Develop
Spell check Release Notes
Merge pull request #460 from Magento/develop

Fix install instrux about 2 directories at start of topic
Merge pull request #461 from Magento/develop

Fix code formatting
Merge pull request #462 from Magento/develop

Hot fix: add xdebug issue to Release Notes
Merge pull request #463 from Magento/develop

Develop
Hot fix for xdebug in Release Notes (clarify it can happen during
installation; also update system requirements)
Merge pull request #464 from Magento/develop

Hot fix for xdebug in Release Notes (clarify it can happen during
Merge pull request #465 from Magento/develop

Spell check Release Notes
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of github.com:magento/devdocs