fix up docs for prune operations
fix up docs for prune operations

- remove extraneous markup
- fix up "would do / actually do" example pairs
- wrap long command lines
- change **** blocks to ---- blocks
- don't say "object" or "object type"; instead, say "resource" and "resource type"
- reprhase default=FOO as default `FOO`; remove (default `false`); add repl-args to table

xiaoping378/openshift-docs,xiaoping378/openshift-docs,xiaoping378/openshift-docs