DOC: Adding example to head and tail method (#16416)

Author: Cheukting

pandas/core/generic.py

@@ -3578,17 +3578,17 @@ def head(self, n=5):
         5     bee
         6    bear
 
-        Viewing the last 5 lines (the default)        
-        >>> df.head()        
+        Viewing the last 5 lines (the default)
+        >>> df.head()
            animal
         0  falcon
         1  parrot
         2    lion
         3  monkey
         4   shark
 
-        Viewing the last n lines (three in this case)        
-        >>> df.head(3)        
+        Viewing the last n lines (three in this case)
+        >>> df.head(3)
            animal
         0  falcon
         1  parrot