doc: Use proper note and warning annotations

The documentation contains plenty of notes and warnings. Enable
special rendering of these blocks by converting the note prefix
into a .. note:: annotation.

Change-Id: I34e26ca6bf313d335672ab6c2645741900338822
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/design/reset-design.rst b/docs/design/reset-design.rst
index b5c9bb4..ccd717a 100644
--- a/docs/design/reset-design.rst
+++ b/docs/design/reset-design.rst
@@ -23,10 +23,11 @@
 guide the platform integrator by indicating which build options exclude which
 steps, depending on the capability of the platform.
 
-Note: If BL31 is used as the TF-A entry point instead of BL1, the diagram
-above is still relevant, as all these operations will occur in BL31 in
-this case. Please refer to section 6 "Using BL31 entrypoint as the reset
-address" for more information.
+.. note::
+   If BL31 is used as the TF-A entry point instead of BL1, the diagram
+   above is still relevant, as all these operations will occur in BL31 in
+   this case. Please refer to section 6 "Using BL31 entrypoint as the reset
+   address" for more information.
 
 Programmable CPU reset address
 ------------------------------