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

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!

Start with the capabilities example linked in the issue and cmocean/tools.py around line 23; run the documented snippet and inspect how print_colormaps handles its input and writes output. Update the documentation example so it no longer raises the reported error, and clarify or verify where its output files should appear.

Written by the indexing model from the issue text.