Reword some text

Dependencies

• [2] VUARRVTI Clean up strings
• [3] TEQJC3HX Add 03-nix-container
• [4] W2G433QU Refactor libdemo and flakeref for nix run commands

Change contents

• replacement in 03-nix-container/demo-inside-nix-develop.sh at line 9
  [3.5856]→[2.2939:3064](∅→∅)
  − h "Now we are inside a development shell that has rootless podman."

  − , "We can manipulate containers just like docker could."
  [3.5856]

  [3.5977]
  + h "Now we are inside a development shell that has podman available."

  + , "Podman is an alternative implementaion of Docker that can also handle OCI containers."

  + , "One of the advantages is that it can run rootless, without a daemon."