DOC: Resolve RT03 errors in several methods #2 (#57785)

* Add return info for nsmallest method

* Add result info on nunique.

* Add return information to pipe method.

* Add return information for boxplot method

* Add return information for kde plot.

* Add result information for scatter plot.

* Remove resolved methods from ignore_functions parameter

* Reinsert method to code checker which was erroneously removed.

ci/code_checks.sh

@@ -623,13 +623,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
         pandas.DataFrame.mean\
         pandas.DataFrame.median\
         pandas.DataFrame.min\
-        pandas.DataFrame.nsmallest\
-        pandas.DataFrame.nunique\
-        pandas.DataFrame.pipe\
-        pandas.DataFrame.plot.box\
-        pandas.DataFrame.plot.density\
-        pandas.DataFrame.plot.kde\
-        pandas.DataFrame.plot.scatter\
         pandas.DataFrame.pop\
         pandas.DataFrame.prod\
         pandas.DataFrame.product\

pandas/core/frame.py

@@ -7432,6 +7432,7 @@ def nsmallest(
         Returns
         -------
         DataFrame
+            DataFrame with the first `n` rows ordered by `columns` in ascending order.
 
         See Also
         --------
@@ -11898,6 +11899,7 @@ def nunique(self, axis: Axis = 0, dropna: bool = True) -> Series:
         Returns
         -------
         Series
+            Series with counts of unique values per row or column, depending on `axis`.
 
         See Also
         --------

pandas/core/generic.py

@@ -5846,7 +5846,8 @@ def pipe(
 
         Returns
         -------
-        the return type of ``func``.
+        The return type of ``func``.
+            The result of applying ``func`` to the Series or DataFrame.
 
         See Also
         --------
@@ -5862,7 +5863,7 @@ def pipe(
 
         Examples
         --------
-        Constructing a income DataFrame from a dictionary.
+        Constructing an income DataFrame from a dictionary.
 
         >>> data = [[8000, 1000], [9500, np.nan], [5000, 2000]]
         >>> df = pd.DataFrame(data, columns=["Salary", "Others"])

pandas/plotting/_core.py

@@ -1335,6 +1335,7 @@ def box(self, by: IndexLabel | None = None, **kwargs) -> PlotAccessor:
         Returns
         -------
         :class:`matplotlib.axes.Axes` or numpy.ndarray of them
+            The matplotlib axes containing the box plot.
 
         See Also
         --------
@@ -1466,6 +1467,7 @@ def kde(
         Returns
         -------
         matplotlib.axes.Axes or numpy.ndarray of them
+            The matplotlib axes containing the KDE plot.
 
         See Also
         --------
@@ -1745,6 +1747,7 @@ def scatter(
         Returns
         -------
         :class:`matplotlib.axes.Axes` or numpy.ndarray of them
+            The matplotlib axes containing the scatter plot.
 
         See Also
         --------