pygmt.grdfill: Add alias "no_data" for "N"

[yvonnefroehlich]

Description of proposed changes

This PR aims to add the alias no_data for N of pygmt.grdfill. Following the Code Style (please see https://www.pygmt.org/dev/contributing.html#code-style) an underscore is used, despite the Julia documentation uses nodata (please see https://www.generic-mapping-tools.org/GMTjl_doc/documentation/modules/grdfill/index.html#grdfill).

Upstream GMT documentation: https://docs.generic-mapping-tools.org/dev/grdfill.html#n

Preview: https://pygmt-dev--2618.org.readthedocs.build/en/2618/api/generated/pygmt.grdfill.html

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