[ci skip] Changes some wording to better foreshadow what is coming up later.
This should prevent some anxiety readers may experience when the doc goes into something different than what it just explained. Also clarifies a statement about priority in engines and application environments

[ci skip] fixes double `the`

[ci skip] more clarifications

[ci skip] changes from tics to quotes
Merge pull request #15941 from variousred/docrails-changes

[ci skip] Changes some wording to better foreshadow what is coming up later