Add 'n' shortcut for new doc

Fixed cmd+enter shortcut to publish doc
Fixed keyboard shortcut display on non-mac
Fixed heading alignment
Fixed documents smaller than page should not scroll

app/components/ClickablePadding.js

@@ -2,9 +2,8 @@
 import styled from 'styled-components';
 
 const ClickablePadding = styled.div`
-  min-height: 50vh;
   cursor: ${({ onClick }) => (onClick ? 'text' : 'default')};
-  ${({ grow }) => grow && `flex-grow: 1;`};
+  ${({ grow }) => grow && `flex-grow: 100;`};
 `;
 
 export default ClickablePadding;