Expose Pinia Colada signals in loaders

[posva]

Currently the signal exposed in query in colada loaders is the one from loaders, tied to the navigation. But in queries, there is another signal related to the query itself.

Merging both signals

We could merge both signals with AbortSignal.any() (newly available so will need a polyfill). This would be partly breaking but seems to be the most intuitive version

Adding both signals individually

We could merge both signals into signal: { navigation, query } and let users merge

Adding a new property to loaders

signals (plural) so the signal is kept