Accessibility: Remove title attributes from the Link Manager screen.

Title attributes are now replaced with `aria-label` where appropriate.
Also fixes some typos in the DocBlocks.

Fixes #35135.
Built from https://develop.svn.wordpress.org/trunk@35998


git-svn-id: https://core.svn.wordpress.org/trunk@35963 1a063a9b-81f0-0310-95a4-ce76da25c4cd