DOC: Expand docstrings for head / tail methods (pandas-dev#16941)

Author: yosukeBaya4

pandas/core/generic.py

@@ -2978,14 +2978,36 @@ def filter(self, items=None, like=None, regex=None, axis=None):
 
     def head(self, n=5):
         """
-        Returns first n rows
+        Return the first n rows.
+
+        Parameters
+        ----------
+        n : int, default 5
+            Number of rows to select.
+
+        Returns
+        -------
+        obj_head : type of caller
+            The first n rows of the caller object.
         """
+
         return self.iloc[:n]
 
     def tail(self, n=5):
         """
-        Returns last n rows
+        Return the last n rows.
+
+        Parameters
+        ----------
+        n : int, default 5
+            Number of rows to select.
+
+        Returns
+        -------
+        obj_tail : type of caller
+            The last n rows of the caller object.
         """
+
         if n == 0:
             return self.iloc[0:0]
         return self.iloc[-n:]