saddle-points: instructions: fix directions

[ee7]

Please double-check that I haven't become confused here.

This PR is a follow-up of #2248 (comment).

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These directions didn't match what we said elsewhere in the instructions:

An acceptable tree will be the largest in its row, while being the smallest in its column.

And in the introduction:

The best tree will be the tallest tree compared to all the other trees to the east and west, so that you have the best possible view of the sunrises and sunsets.

You don't like climbing too much, so the perfect tree will also be the shortest among all the trees to the north and to the south.

And in the test cases:

Here is a grid that has exactly one candidate tree.

    1  2  3  4
  |-----------
1 | 9  8  7  8
2 | 5  3  2  4  <--- potential tree house at row 2, column 1, for tree with height 5
3 | 6  6  7  1

• Row 2 has values 5, 3, and 1. The largest value is 5.
• Column 1 has values 9, 5, and 6. The smallest value is 5.

So the point at [2, 1] (row: 2, column: 1) is a great spot for a tree house.

Fixes: #2263

[IsaacG]

The grid isn't oriented with North at the top. This was previously called out and is being discussed but the exercise is internally consistent.

[kytrinyx]

Please double-check that I haven't become confused here.

😂 I feel like this is the story of my life!