Comment body is more legible on tablet and up

Sets the line-height a bit higher to make comments more legible.

Line-height was set to 20px on paragraphs and 22px on the rest.

Change proposed by Chris P, you can discuss with him.

![ ](http://4.bp.blogspot.com/-pJrU_3aH2zY/UpY2Uw3NsvI/AAAAAAABDys/2opGDJKWgI0/s1600/1.gif)