TYP: Add type hints support for pygmt.datasets.load_sample_data

[seisman]

Description of proposed changes

Address #2812.

Preview: https://pygmt-dev--2859.org.readthedocs.build/en/2859/api/generated/pygmt.datasets.load_sample_data.html#pygmt.datasets.load_sample_data

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.
• Use underscores (not hyphens) in names of Python files and directories.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[yvonnefroehlich]

So far in line 313 (currently) or 324 (after this PR):

pygmt/pygmt/datasets/samples.py

Lines 311 to 315 in 09f2452

	Parameters
	----------
	name : str
	Name of the dataset to load.

was not changed to

name

Analogous as done for data_source in PR #2849.

pygmt/pygmt/datasets/earth_relief.py

Lines 77 to 81 in 09f2452

	for all resolutions except ``"15s"`` which is ``"pixel"`` only.
	data_source
	Select the source for the Earth relief data. Available options are:

Or was this intended because the list of available input names is a bit longer?

[seisman]

Fixed in 10a7ce4. Now it looks like:

Yes, it's a little bit longer, but I feel it's still acceptable.