Update syntax highlighting, update allUnique

snippets/difference.md

@@ -6,11 +6,11 @@ Returns the difference between two iterables.
 
 Use list comprehension to only keep values not contained in `b`.
 
-```python
+```py
 def difference(a, b):
     _b = set(b)
     return [item for item in a if item not in _b]
 ```
-``` python
+```py
 difference([1, 2, 3], [1, 2, 4]) # [3]
 ```