doc don't `zap` user-created content

per discussion in https://github.com/caskroom/homebrew-cask/pull/6174#discussion-diff-17516171
refs: #6174
protect against inner ".." in uninstall paths
Add the Mailpile beta
Merge pull request #6199 from jamesottaway/mailpile-beta

Add the Mailpile beta
Merge pull request #6189 from rolandwalker/doc_zap_user_content

doc don't `zap` user-created content
Merge pull request #6193 from rolandwalker/double_dot_is_relative

protect against inner ".." in uninstall paths
double slash in airstream
double slash in apache-directory-studio
double slash in microsoft-lync-plugin
zap stanza from mackup for adium.rb
zap stanza from mackup for atom.rb
zap stanza from mackup for awareness.rb
zap stanza from mackup for bartender.rb
zap stanza from mackup for bettertouchtool.rb
zap stanza from mackup for bibdesk.rb
zap stanza from mackup for brackets.rb
zap stanza from mackup for caffeine.rb
zap stanza from mackup for charles.rb
zap stanza from mackup for chicken.rb
zap stanza from mackup for clementine.rb