Change 'Hopp' to 'Hop'
Add a space between Code and Climate
Fix the markup.

Markdown is not allowed inside HTML, so just use HTML.
Rename 'that' to 'the'

'Assign that arguments' does not make sense. 'Assign the arguments' does.
Merge pull request #561 from mattr-/update-refactoring-tutorial

Update refactoring tutorial