[ENH]: expand connectionPatch coords to support all annotation coords

還沒有人認領這個 Issue。

### Problem

ConnectionPatch is described as annotation w/o text in the tutorial and as a function for connecting two aribtrary points in its docs and it would be very helpful if those two points could be artists. Since annotation supports this, I'm doing a lot of

```python

arrow = ax.annotate("", (x1, y1), (x2, y2), xycoords=A1, textcoords=A2, arrowprops=dict(arrowstyle='-|>'))
label = ax.annotate("label", (xp, yp), xycoords=arrow)
```

and I'd really rather prefer to use the object with "connect thing" semantics for connecting things and the object with "label things" semantics for labeling.

### Proposed solution

@anntzer proposed factoring out the annotation coordinate system in https://github.com/matplotlib/matplotlib/issues/22223#issuecomment-1011957191 and that's the approach I'd advocate here -> pull out the coordinate logic into its own logic and then have ConnectionPatch call out to that function.

先閱讀 ConnectionPatch 和註解座標的處理方式，然後檢視 issue #22223 中提出的座標系分解方法。當 ConnectionPatch 支援此處描述的註解座標形式（包括藝術家座標），同時保留其連接語義時，這項工作就完成了。

由索引模型根據 Issue 內容生成。