AliasSystem: Migrate the 'registration' parameter to the new alias system and support descriptive arguments

[seisman]

GMT documentation: https://docs.generic-mapping-tools.org/6.6/gmt.html#nodereg-full

The GMT CLI syntax is -r[g|p]. Here, we use the descriptive values "gridline" and "pixel".

I'm still thinking if we should support the GridRegistration enums (https://www.pygmt.org/dev/api/generated/pygmt.enums.GridRegistration.html#pygmt.enums.GridRegistration), i.e.,

import pygmt
from pygmt.enums import GridRegistration

pygmt.xyz2grd(..., registration=GridRegistration.PIXEL)

@GenericMappingTools/pygmt-maintainers What do you think?

[weiji14]

thinking if we should support the GridRegistration enums

Ideally yes, but probably do in another PR. Not sure how easy it is to convert an IntEnum to support StrEnum also (maybe ReprEnum?).

[weiji14]

Docstring for registration should be updated to 1) add bool type hint, and 2) indicate that registration=True means pixel registration.

pygmt/pygmt/helpers/decorators.py

Lines 279 to 283 in 25f2656

	"registration": r"""
	registration : str
	**g**\|\ **p**.
	Force gridline (**g**) or pixel (**p**) node registration
	[Default is **g**\ (ridline)].""",

[seisman]

add bool type hint,

Type hints are now added via function signatures, not in docstrings.