[QA] Use standard prompt for session examples
[Tr] Minor grammar fix
Use moonscript for awesome example

These docs are aimed mostly at co-workers, and our default configurations are
all moonscript nowadays.
[Tr] Use the 'samp' directive for value documentation
[QA] Fix location for default XDG_DATA_HOME
Switch to click for command line processing
Favour click's echo over print

It behaves nicer on poorly configured systems.
Update help formatting to match click's style
Allow setting of common options with envvars

Thanks to click for making this easy.
Use click's built-in version_option option
Use click's builtin test support

Much nicer than all the manual patching.
[Tr] Update click callback to 2.0 signature
Use number of warnings as exit code in fsck
Use click's isolated_filesystem support in tests
Use click's atomic file writing
Switch to click's colourised output
Sync docs with new help formatting

See ec5f3b31a4558a3de5663fa6019d65a3e62733c7.
Document envvar usage
Use click's paging function when displaying long output