Add docstrings for ChangingDecimal and ChangeDecimalToValue (#4346)

Co-authored-by: Francisco Manríquez Novoa <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

manim/animation/numbers.py

@@ -16,6 +16,41 @@
 
 
 class ChangingDecimal(Animation):
+    """Animate a :class:`~.DecimalNumber` to values specified by a user-supplied function.
+
+    Parameters
+    ----------
+    decimal_mob
+        The :class:`~.DecimalNumber` instance to animate.
+    number_update_func
+        A function that returns the number to display at each point in the animation.
+    suspend_mobject_updating
+        If ``True``, the mobject is not updated outside this animation.
+
+    Raises
+    ------
+    TypeError
+        If ``decimal_mob`` is not an instance of :class:`~.DecimalNumber`.
+
+    Examples
+    --------
+
+    .. manim:: ChangingDecimalExample
+
+        class ChangingDecimalExample(Scene):
+            def construct(self):
+                number = DecimalNumber(0)
+                self.add(number)
+                self.play(
+                    ChangingDecimal(
+                        number,
+                        lambda a: 5 * a,
+                        run_time=3
+                    )
+                )
+                self.wait()
+    """
+
     def __init__(
         self,
         decimal_mob: DecimalNumber,
@@ -38,6 +73,28 @@ def interpolate_mobject(self, alpha: float) -> None:
 
 
 class ChangeDecimalToValue(ChangingDecimal):
+    """Animate a :class:`~.DecimalNumber` to a target value using linear interpolation.
+
+    Parameters
+    ----------
+    decimal_mob
+        The :class:`~.DecimalNumber` instance to animate.
+    target_number
+        The target value to transition to.
+
+    Examples
+    --------
+
+    .. manim:: ChangeDecimalToValueExample
+
+        class ChangeDecimalToValueExample(Scene):
+            def construct(self):
+                number = DecimalNumber(0)
+                self.add(number)
+                self.play(ChangeDecimalToValue(number, 10, run_time=3))
+                self.wait()
+    """
+
     def __init__(
         self, decimal_mob: DecimalNumber, target_number: int, **kwargs: Any
     ) -> None: