* Revert "Account for empty string regexp in lineinfile (#41451)"
This reverts commit 4b5b4a760c.
* Use context managers for interacting with files
* Store line and regexp parameters in a variable
* Add warning when regexp is an empty string
* Remove '=' from error messages
* Update warning message and add changelog
* Add tests
* Improve warning message
Offer an equivalent regexp that won't trigger the warning.
Update tests to match new warning.
* Add porting guide entry for lineinfile change
