Bundled themes: Prevent the arrow in "Continue reading" links from wrapping to a second line.

props DustinHartzler, dominik.schwind.
fixes #27908.
Built from https://develop.svn.wordpress.org/trunk@29771


git-svn-id: http://core.svn.wordpress.org/trunk@29543 1a063a9b-81f0-0310-95a4-ce76da25c4cd