Update 03_operators.md

## Summary
Fixed a small issue in the comparison operator examples. The original text described the `not in` operator but didn’t include a working example or had a typo.

## Changes Made
- Added missing example for `not in` comparison
- Corrected description from `(x in y)` to `(x not in y)`

## Why This Change Was Needed
This makes the tutorial more accurate and consistent. The previous version could confuse beginners since the explanation didn’t match the examples.

## Example Output
```python
print('B not in Asabeneh:', 'B' not in 'Asabeneh')  # True

03_Day_Operators/03_operators.md

@@ -213,13 +213,13 @@ In addition to the above comparison operator Python uses:
 - _is_: Returns true if both variables are the same object(x is y)
 - _is not_: Returns true if both variables are not the same object(x is not y)
 - _in_: Returns True if the queried list contains a certain item(x in y)
-- _not in_: Returns True if the queried list doesn't have a certain item(x in y)
+- _not in_: Returns True if the queried list doesn't have a certain item(x not in y)
 
 ```py
 print('1 is 1', 1 is 1)                   # True - because the data values are the same
 print('1 is not 2', 1 is not 2)           # True - because 1 is not 2
 print('A in Asabeneh', 'A' in 'Asabeneh') # True - A found in the string
-print('B in Asabeneh', 'B' in 'Asabeneh') # False - there is no uppercase B
+print('B not in Asabeneh', 'B' in 'Asabeneh') # False - there is no uppercase B
 print('coding' in 'coding for all') # True - because coding for all has the word coding
 print('a in an:', 'a' in 'an')      # True
 print('4 is 2 ** 2:', 4 is 2 ** 2)   # True