The complication here is that we need to take extra care to avoid
issuing self-vanishing/repeated togglings of the same pin/band,
as multiple graph nodes correspond to the same one (at least in case of polygons)
- refactor(layout): move reusable functions from Overlay to Layout
I ran the following command in Fish shell:
```
reuse annotate --skip-unrecognised --copyright="Topola contributors" --license="MIT" **.{rs,md,toml}
```
The choice of year 2024 in the copyright statements is intentional.