In the S3 bucket, the file cluster.spec is not actually the spec, but the
actual configuration. The file config is the spec. To avoid confusion,
this commit changes spec/specification into 'desired configuration' in
the documentation, to avoid associating cluster.spec with a cluster
'specification' that the users should use.
* Use the pretty.LongDesc function (which doesn't pipe it through
markdown -> ascii)
* Use pretty.Bash helper to avoid problems with backticks in
go-backtick-quoted-strings
* Make sure indentation is consistent