add Copilot PR review instructions (#19738)
Summary of the issue:
CoPilot PR reviews and agent work can be improved by writing instructions files.
This can minimize the work of NV Access, by automating some common review feedback we create.
Description of user facing changes:
None
Description of developer facing changes:
Improved CoPilot review instructions.
Fixed up user guide standards issues
Description of development approach:
Used CoPilot to generate, edited
Copied sections from other human facing docs and edited to simplify
