Alter code_flow_node type

What does this MR do?

Changes the code_flow_node type from code_flow_node to code-flow-node to align to existing named-list, file-location and module-location .

What are the relevant issue numbers?

This is related to @adamcohen's comment on a previous MR: !159 (comment 1938337496)

Checklist

• Ensure changes can be built upon without requiring a breaking change, see Building for Extensibility.
• Review and add/update tests for this feature/bug.
• Add an entry to the CHANGELOG if required, with the appropriate version. See Classifying Changes.
• Assign the MR to the appropriate person/people for review.