The default mode writes the updated roadmap to standard output:
mapsplice replace docs/roadmap.md 8 replacement.md > rewritten.md
Non-empty rendered roadmaps end in exactly one final newline. A second
mapsplice render of conformant output does not add another final newline.
Use in-place mode when the target should be rewritten directly:
mapsplice --in-place delete docs/roadmap.md 8
When --in-place is used, mapsplice rewrites the target and does not emit
the roadmap body on standard output.
If validation fails in --in-place mode, the target file is left unchanged and
no roadmap body is emitted on standard output.