Change first heading to overview

Booting/linux-bootstrap-2.md

@@ -1,7 +1,7 @@
 Kernel booting process. Part 2.
 ================================================================================
 
-First steps in the kernel setup
+Overview
 --------------------------------------------------------------------------------
 
 We started to dive into linux kernel internals in the previous [part](linux-bootstrap-1.md) and saw the initial part of the kernel setup code. We stopped at the first call to the `main` function (which is the first function written in C) from [arch/x86/boot/main.c](https://github.com/torvalds/linux/blob/master/arch/x86/boot/main.c).