Fix various issues with docs (#494)

* Fix typo: ther -> the

* Consistent casing in help messages

* Update versions in docs to latest

* Consistent forked process names in design docs

* Update package list in rockylinux

* Fix indentation in pgcopydb help message

* Fix typo: Create and exports -> Create and export

* Update some version outputs

* Fix typo

* Update version output using official docker image