DOC: clarify np.searchsorted documentation and add example for sorter

Author: HabibiHye

numpy/_core/fromnumeric.py

@@ -1535,7 +1535,8 @@ def searchsorted(a, v, side='left', sorter=None):
     >>> np.searchsorted([11,12,13,14,15], [-10, 20, 12, 13])
     array([0, 5, 1, 2])
 
-    When `sorter` is used, the returned indices refer to the sorted array of 'a' and not a itself:
+    When `sorter` is used, the returned indices refer to the sorted
+    array of 'a' and not 'a' itself:
 
     >>> a = np.array([40, 10, 20, 30])
     >>> sorter = np.argsort(a)