Upgrade dev-cmd and document commands & tasks.

[jsirois]

Now:

:; uvrc -l
Commands:
(5 commands are hidden.)
check-python-version
fmt
check-fmt
lint
check-lint
type-check
doc
    -type: The type of sphinx doc to build. One of:
           html, dirhtml, htmlhelp, qthelp, devhelp, text, gettext, linkcheck or xml.
           [default: html]

Tasks:
test
linkcheck: Check documentation for broken links.
package: Build the science scies using science from local sources.
science: Runs science from local sources. Accepts extra args after --.
checks: Runs all development checks, including auto-formatting code.
ci: Runs all checks used for CI.