RSS widgets: Omit the title attribute when the summary is shown.

Trim the title attribute to ensure whitespace isn't rendered.

props SergeyBiryukov.
fixes #26520. see #26552.

Built from https://develop.svn.wordpress.org/trunk@27691


git-svn-id: http://core.svn.wordpress.org/trunk@27530 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Use the current post's post type when determining post adjacency.

props ethitter.
fixes #26937.

Built from https://develop.svn.wordpress.org/trunk@27692


git-svn-id: http://core.svn.wordpress.org/trunk@27531 1a063a9b-81f0-0310-95a4-ce76da25c4cd