doc: Reformat RST content for Sphinx rendering

Some existing RST files contain formatting errors that will cause
Sphinx to generate warnings.

Change-Id: I714136d1ea5b645eaa55dd304fb56d5b5fd18ee1
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/design.rst b/docs/design.rst
index 91815d0..4df620c 100644
--- a/docs/design.rst
+++ b/docs/design.rst
@@ -1,10 +1,5 @@
-Trusted Firmware-A Tests - Design
-=================================
-
-.. section-numbering::
-    :suffix: .
-
-.. contents::
+Design
+======
 
 This document provides some details about the internals of the TF-A Tests
 design. It is incomplete at the moment.