DOC: extra code blocks in the user guide

[ziw-liu]

Describe the issue linked to the documentation

Each code block is followed by an empty one on RTD:

The markdown source code is correct though.

Suggested fix for documentation

No response

[ianhi]

I'm pretty sure that those are meant to be output blocks. however there is no output from those code blocks. To remove teh blank thing which i agree is confusing you need to remove or change teh result="ansi"