Fixed typo in 19.2

'modern' was spelled as 'mordern' in both the good and bad examples of section 19.2

Author: Ryan-McBride

README.md

@@ -1466,14 +1466,14 @@
  firstName: 'Florence',
  - lastName: 'Nightingale'
  + lastName: 'Nightingale',
- + inventorOf: ['coxcomb graph', 'mordern nursing']
+ + inventorOf: ['coxcomb graph', 'modern nursing']
  }
 
  // good - git diff with trailing comma
  const hero = {
  firstName: 'Florence',
  lastName: 'Nightingale',
- + inventorOf: ['coxcomb chart', 'mordern nursing'],
+ + inventorOf: ['coxcomb chart', 'modern nursing'],
  }
 
  // bad