context function 2: find-path-between

find-path-between:
    description:
        find-path-between(ket1, ket2)
        Use Dijkstra's algorithm to find the shortest path between ket1 and ket2
        See: https://en.wikipedia.org/wiki/Dijkstra%27s_algorithm
        To instead find the operators required to get from ket1 to ket2 see find-operators-between().

    examples:
        -- learn a grid, then find a path:
        learn-grid[10, 10]
        find-path-between(|grid: 0: 0>, |grid: 5: 5>)
            |grid: 0: 0> . |grid: 1: 1> . |grid: 2: 2> . |grid: 3: 3> . |grid: 4: 4> . |grid: 5: 5>

    see also:
        find-operators-between