`combine_merged_cells` cannot capture all merges

Merges are actually just one value in the top left cell, and some metadata. If the top-left cell is not in your requested range, you cannot faithfully recreate the merge. For example:


If you called `worksheet.get_values("F3:H4", combine_merged_cells=True)`, what would you expect?

1

| "big merge" | 2 | 3 |
| --- | --- | --- |
| 4 | 5 | 6 |

or 2

| | 2 | 3 |
| --- | --- | --- |
| 4 | 5 | 6 |

We cannot recreate 1 without added complexity. We must return 2. This may be unexpected.

`combine_merged_cells` was added in #1215. Its addition has brought several problems (#1298, #1330).

What should we do? If we leave it in, it will always have this issue. If we remove it, it will be sad.

Start by reading the combine_merged_cells addition in #1215, then review the related reports in #1298 and #1330 alongside this issue. Determine whether the option should remain or be removed, and define the expected behavior for ranges whose top-left merged cell is outside the request. Done requires a maintainer-approved resolution.

Written by the indexing model from the issue text.