x86/Documentation: Make Literal Blocks to follow reStructuredText specification

x86/Documentation: Make Literal Blocks to follow reStructuredText specification

The file collects pieces from different epochs and hence has unaligned
style of the Literal Blocks (in terms of reStructuredText specification).
Make the Literal Blocks to follow the reStructuredText specification

While at it, make the C-like code more C and follow the Kernel Coding
style in them (after satisfying rST specification).

Suggested-by: Ingo Molnar <mingo@kernel.org>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20241128152546.2396782-2-andriy.shevchenko@linux.intel.com