docs: document c-style cast prohibition

Author: PastaPastaPasta

doc/developer-notes.md

@@ -104,6 +104,10 @@ code.
   - `++i` is preferred over `i++`.
   - `nullptr` is preferred over `NULL` or `(void*)0`.
   - `static_assert` is preferred over `assert` where possible. Generally; compile-time checking is preferred over run-time checking.
+  - Use a named cast or functional cast, not a C-Style cast. When casting
+    between integer types, use functional casts such as `int(x)` or `int{x}`
+    instead of `(int) x`. When casting between more complex types, use static_cast.
+    Use reinterpret_cast and const_cast as appropriate.
 
 Block style example:
 ```c++