`cmocean.tools.print_colormaps` snippet in the docs raises an error

还没有人认领这个 Issue。

Hello! I love your work, this is my favorite set of colormaps.

Today I wanted to run some code from [the docs](https://matplotlib.org/cmocean/#capabilities):

```python
import cmocean

cmaps = cmocean.cm.cmap_d
cmocean.tools.print_colormaps(cmaps)
```

and it produces the following exception and traceback:

```
Traceback (most recent call last):
File "/home/mfisher/Projects/_test/extend-colormaps-js/test.py", line 4, in
cmocean.tools.print_colormaps(cmaps)
File "/home/mfisher/Projects/_test/extend-colormaps-js/.pixi/envs/default/lib/python3.12/site-packages/cmocean/tools.py", line 25, in print_colormaps
rgbtemp = cmap(np.linspace(0, 1, N))[np.newaxis, :, :3][0]
^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: 'str' object is not callable
```

The issue appears to be here:

https://github.com/matplotlib/cmocean/blob/59c35002c3aa5296b65d9646e52604c627441eb6/cmocean/tools.py#L23

We loop over the `cmaps` object, which is a dictionary of colormap name keys to colormap object values in this invocation, but the function expects the object to be a list of colormap objects.

So the docs could be updated to:

```python
import cmocean

cmaps = cmocean.cm.cmap_d
cmocean.tools.print_colormaps(cmaps.values())
```

But after running this code I don't see the output files!

从 issue 中链接的 capabilities 示例以及第 23 行附近的 cmocean/tools.py 开始；运行文档中的代码片段，并检查 print_colormaps 如何处理输入以及写入输出。更新文档示例，使其不再引发所报告的错误，并明确或验证其输出文件应出现在哪里。

由索引模型根据 Issue 内容生成。