Fixes multi-line strings with missing spaces

Multi-line concatenated strings are easily given bad spacing:

  "This looks like"
  "it will be OK"    => "This looks likeit will be OK"

This patch fixes those. I don't think it's possible to create
a hacking rule for this as any automated check will generate
too many false positives.

Change-Id: If89007f45d90ca5321336e3623139f9538ac06b8
Merge "Fixes multi-line strings with missing spaces"