chore: fix doc comment indentation

The paragraph refers to the two items in the previous numbered list,
so it must not be indented.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: bonzini

src/volatile_memory.rs

@@ -16,12 +16,15 @@
 //! doing with that hunk of memory.
 //!
 //! For the purposes of maintaining safety, volatile memory has some rules of its own:
+//!
 //! 1. No references or slices to volatile memory (`&` or `&mut`).
+//!
 //! 2. Access should always been done with a volatile read or write.
-//!    The First rule is because having references of any kind to memory considered volatile would
-//!    violate pointer aliasing. The second is because unvolatile accesses are inherently undefined if
-//!    done concurrently without synchronization. With volatile access we know that the compiler has
-//!    not reordered or elided the access.
+//!
+//! The First rule is because having references of any kind to memory considered volatile would
+//! violate pointer aliasing. The second is because unvolatile accesses are inherently undefined if
+//! done concurrently without synchronization. With volatile access we know that the compiler has
+//! not reordered or elided the access.
 
 use std::cmp::min;
 use std::io::{self, Read, Write};