chore: Don't assume sudo for MacPorts install

chore: Adapt install script for Illumos and Solaris

chore: Don't display skipped checks in doctor command output

fix: Apply .chezmoiignore to externals

chore: Fix panic when .chezmoidata or .chezmoiexternal did not have a…

…n extension

feat: Re-enable building with Go 1.16

chore: Document more internal functions

chore: Update dependencies

Merge pull request twpayne#1448 from twpayne/source-dir-not-root

Detect when the source directory is already in a git working copy

Add doc on detemining whether the machine is a laptop or desktop