cbectl documentation needs updating

Noticed that the cbectl options don't appear to match what is offered in the tool.
For example in 5.5.3/6.0 the tool offers the ability to change.

• num_reader_threads
• num_writer_threads
• num_auxio_threads
• num_nonio_threads

But the documentation refers to

• max_num_readers
• max_num_writers
• max_num_auxio
• max_num_nonio

6.0 docl
5.5 doc

The set of available options are documented in the code at the following
5.5.3 code doc
6.0 code doc

Also the limit described in the Performance tuning options
"All these options can be used only to tune down the number of threads: if the value was set as N at initial startup, then only a value < N will work."
is now outdated (as of 5.0) given the following MB-22041