Guides: minor typo fixed [ci skip]
Merge pull request #14652 from Emily/duration_eqls

Fixed problem where `1.day.eql?(1.day)` is false
Merge pull request #14653 from vdmgolub/patch-1

Guides: minor typo fixed in Asset Pipeline guide
upgrading section for 4.1 is no longer WIP. [ci skip]
Added request.script_name to Mailer Preview links

This helps correct links for apps running on a sub directory on the
mailer index pages.