Move note about forgetting to reserve space outside of a warning box (#166)

Author: avivace

src/part1/header.md

@@ -122,13 +122,7 @@ So the `jp` at $0100 went there, and started executing instructions (`3E CE` is
 But why is `EntryPoint` there?
 Well, as you may have figured out from the warnings RGBFIX printed, it *overwrites* the header area in the ROM.
 However, RGBLINK is **not** aware of the header (because RGBLINK is not only used to generate ROMs!), so you must explicitly reserve space for the header area.
-
-:::danger Common mistake
-
-Forgetting to reserve this space, and having a piece of code or data ending up there then overwritten, is a common beginner mistake that can be quite puzzling.
-Fortunately, RGBFIX since version 0.5.1 warns when it detects this mistake, as shown above.
-
-:::
+Forgetting to do so is a common beginner mistake — code or data can end up there and get silently overwritten, which RGBFIX will warn you about as shown above.
 
 So, we prevent disaster like this: