Fix small headings

Author: mstephen19

content/academy/switching_to_typescript/unknown_and_type_casting.md

@@ -6,7 +6,7 @@ paths:
     - switching-to-typescript/unknown-and-type-casting
 ---
 
-## [](#unknown-and-type-casting) Unknown & type casting
+# [](#unknown-and-type-casting) Unknown & type casting
 
 There are two types we haven't discussed yet - `any` and `unknown`.
 

content/academy/switching_to_typescript/using_types_continued.md

@@ -6,7 +6,7 @@ paths:
     - switching-to-typescript/using-types-continued
 ---
 
-## [](#using-types-continued) Using types (continued)
+# [](#using-types-continued) Using types (continued)
 
 Now that you're (hopefully) fairly comfortable with strings, booleans, and numbers in TypeScript, we can start discussing the more complex types supported by the language.