Figure.colorbar: Migrate the 'truncate' parameter to the new alias system (#4216)

Author: seisman

pygmt/src/colorbar.py

@@ -7,19 +7,17 @@
 
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
-from pygmt.helpers import build_arg_list, fmt_docstring, kwargs_to_strings, use_alias
+from pygmt.helpers import build_arg_list, fmt_docstring, use_alias
 from pygmt.params import Box
 
 __doctest_skip__ = ["colorbar"]
 
 
 @fmt_docstring
-@use_alias(
-    C="cmap", D="position", G="truncate", L="equalsize", Q="log", W="scale", Z="zfile"
-)
-@kwargs_to_strings(G="sequence", I="sequence")
-def colorbar(
+@use_alias(C="cmap", D="position", L="equalsize", Q="log", W="scale", Z="zfile")
+def colorbar(  # noqa: PLR0913
     self,
+    truncate: Sequence[float] | None = None,
     shading: float | Sequence[float] | bool = False,
     projection: str | None = None,
     box: Box | bool = False,
@@ -59,6 +57,7 @@ def colorbar(
     {aliases}
        - B = frame
        - F = box
+       - G = truncate
        - I = shading
        - J = projection
        - R = region
@@ -99,11 +98,11 @@ def colorbar(
         rectangular box is drawn using :gmt-term:`MAP_FRAME_PEN`. To customize the box
         appearance, pass a :class:`pygmt.params.Box` object to control style, fill, pen,
         and other box properties.
-    truncate : list or str
-        *zlo*/*zhi*.
-        Truncate the incoming CPT so that the lowest and highest z-levels are
-        to *zlo* and *zhi*. If one of these equal NaN then we leave that end of
-        the CPT alone. The truncation takes place before the plotting.
+    truncate
+        (*zlow*, *zhigh*).
+        Truncate the incoming CPT so that the lowest and highest z-levels are to *zlow*
+        and *zhigh*. If one of these equal NaN then we leave that end of the CPT alone.
+        The truncation takes place before the plotting.
     scale : float
         Multiply all z-values in the CPT by the provided scale. By default,
         the CPT is used as is.
@@ -161,6 +160,7 @@ def colorbar(
 
     aliasdict = AliasSystem(
         F=Alias(box, name="box"),
+        G=Alias(truncate, name="truncate", sep="/", size=2),
         I=Alias(shading, name="shading", sep="/", size=2),
     ).add_common(
         B=frame,