Add Task headers

Author: kochaika

Variables/Assignments/task.md

@@ -5,6 +5,7 @@ assignment statement, such as `+=`, `-=`, etc.
 
 An augmented assignment expression like `x += 1` can be rewritten as `x = x + 1` to achieve a similar effect.
 You can read more about this <a href="https://docs.python.org/3/reference/simple_stmts.html#augmented-assignment-statements">here</a>.
+
 ### Task
 Use an augmented assignment to add `5` to `number` and update the variable.  
 

Variables/Undefined variable/task.md

@@ -3,6 +3,7 @@
 Variable names may only contain Latin letters, digits, and/or the underscore 
 character, and they cannot start with a digit. They also cannot be any of the 
 reserved <a href="https://docs.python.org/3/reference/lexical_analysis.html#keywords">keywords</a>.
+
 ### Task
 Check what happens if you use a variable which is not defined yet. Change and run the code in the editor – try to print out an **undefined** name (i.e. type the name of an undefined variable inside the brackets of the `print` statement).  
 This should cause an exception - a `NameError`.