Fix |phpversion| rendering literally as **8.5** in Docker commands; update installation.md too - #8344

Fix |phpversion| rendering literally as **8.5** in Docker commands; update installation.md too#8344

markstory merged 2 commits into

cakephp:5.xcakephp/docs:5.xfrom

Nelwhix:fix/docker-quickstart-followupNelwhix/docs-1:fix/docker-quickstart-followupCopy head branch name to clipboard