Add alias 'registration' to methods blockmean, info, grdfilter, surface

[maxrjones]

Description of proposed changes

This PR fixes the format of the registration alias in pygmt/helpers/decorators.py and adds the alias to the wrapped modules that support the -r common option. It also revises the description for the -r option slightly, since some modules that support -r do not involve output grids.

Fixes #

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 adding new functionality, add an example to docstrings or tutorials.

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[seisman]

Looks good. Perhaps change the PR title to "Add alias 'registration' to methods blockmean, info, grdfilter, surface".