Watch growth of multiple files or directories (like `tail -f`)

Current version:

Homepage: https://www.unicom.com/sw/xtail

Formula history

Zhiming Wang xtail: fix test (#5481)
Viktor Szakats xtail: use https homepage
Baptiste Fontaine xtail: use an https url
Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Ted Pennings Convert all 'def test' formulae to 'test do'