doc: Remove backquotes from external hyperlinks

Since Sphinx 2.3.0 backquotes are replaced to \textasciigrave{} during
building latexpdf. Using this element in a \sphinxhref{} breaks the
build. In order to avoid this error backquotes must not be used in
external hyperlinks.

Signed-off-by: Imre Kis <imre.kis@arm.com>
Change-Id: Ie3cf454427e3d5a7b7f9829b42be45aebda7f0dd
diff --git a/docs/components/exception-handling.rst b/docs/components/exception-handling.rst
index 3f38685..e330a62 100644
--- a/docs/components/exception-handling.rst
+++ b/docs/components/exception-handling.rst
@@ -467,7 +467,7 @@
 Non-secure world to request Secure services. They're broadly classified as
 *Fast* or *Yielding* (see `SMCCC`__).
 
-.. __: `http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html`
+.. __: http://infocenter.arm.com/help/topic/com.arm.doc.den0028a/index.html
 
 -  *Fast* SMCs are atomic from the caller's point of view. I.e., they return
    to the caller only when the Secure world has finished serving the request.
@@ -621,6 +621,6 @@
 
 --------------
 
-*Copyright (c) 2018-2019, Arm Limited and Contributors. All rights reserved.*
+*Copyright (c) 2018-2020, Arm Limited and Contributors. All rights reserved.*
 
 .. _SDEI specification: http://infocenter.arm.com/help/topic/com.arm.doc.den0054a/ARM_DEN0054A_Software_Delegated_Exception_Interface.pdf