fix(docs): prevent notation from being eaten by MDC (#375)

content/docs/05.developer-guide/03.variables/02.basic-usage.md

@@ -19,7 +19,7 @@ You can output variables directly inside an expression. For example, if the cont
 {{ foo }}
 ```
 
-You can use the dot (.) notation to access the attributes of variables. If the attribute contains a special character, you can use the subscript notation ([]) instead.
+You can use the dot (`.`) notation to access the attributes of variables. If the attribute contains a special character, you can use the subscript notation (`[]`) instead.
 ```twig
 {{ foo.bar }} # Attribute 'bar' of 'foo'
 {{ foo.bar.baz }} # Attribute 'baz' of attribute 'bar' of 'foo'
@@ -28,7 +28,7 @@ You can use the dot (.) notation to access the attributes of variables. If the a
 ```
 
 ::alert{type="warning"}
-You will see a lot of tasks with hyphenated names in the documentation. When using hyphenated names, you must use the subscript notation ([]) to access any task variables as `-` is a Pebble special character.
+You will see a lot of tasks with hyphenated names in the documentation. When using hyphenated names, you must use the subscript notation (`[]`) to access any task variables as `-` is a Pebble special character.
 ::