Docs: Enable Sphinx tabs extension

Enable the Sphinx tabs extension and fix the 'sphinx-trd-theme' typo.

Signed-off-by: Summer Qin <summer.qin@arm.com>
Change-Id: I18568465804f93e6cd2b71e344a673580cec993b
diff --git a/docs/conf.py.in b/docs/conf.py.in
index b4430c9..e2cd0be 100644
--- a/docs/conf.py.in
+++ b/docs/conf.py.in
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #-------------------------------------------------------------------------------
-# Copyright (c) 2019-2020, Arm Limited. All rights reserved.
+# Copyright (c) 2019-2021, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -50,7 +50,8 @@
     'm2r', #Support markdown files. Needed for external code.
     'sphinx.ext.autosectionlabel', #Make sphinx generate a label for each section
     'sphinxcontrib.plantuml', #Add support for PlantUML drawings
-    'sphinxcontrib.rsvgconverter' #Add support for SVG to PDF
+    'sphinxcontrib.rsvgconverter', #Add support for SVG to PDF
+    'sphinx_tabs.tabs' #Enable tab extension in Sphinx
 ]
 
 #Location of PlantUML
diff --git a/docs/getting_started/tfm_sw_requirement.rst b/docs/getting_started/tfm_sw_requirement.rst
index 03f5629..c37750d 100644
--- a/docs/getting_started/tfm_sw_requirement.rst
+++ b/docs/getting_started/tfm_sw_requirement.rst
@@ -15,7 +15,7 @@
 
 TF-M officially supports a limited set of build environments and setups. In
 this context, official support means that the environments listed below
-are actively used by team members and active developers hence users should
+are actively used by team members and active developers, hence users should
 be able to recreate the same configurations by following the instructions
 described below. In case of problems, the TF-M team provides support
 only for these environments, but building in other environments can still be
@@ -345,7 +345,8 @@
    "Sphinx","=1.7.9","User Guide"
    "sphinxcontrib-plantuml",,"User Guide"
    "sphinxcontrib-svg2pdfconverter",,"User Guide"
-   "sphinx-trd-theme",,"User Guide"
+   "sphinx-rtd-theme",,"User Guide"
+   "sphinx-tabs",,"User Guide"
    "Git",,
    "PlantUML",">v1.2018.11","Reference Manual, User Guide"
    "Graphviz dot",">v2.38.0","Reference manual"
@@ -373,6 +374,7 @@
     state u_guide as "User Guide" <<doc>>
     state refman as "Reference Manual" <<doc>>
     state rtd_theme as "sphinx-rtd-theme" <<doc>>
+    state tabs as "sphinx-tabs" <<doc>>
     state sphnix_puml as "sphinxcontrib-plantuml" <<doc>>
     state sphnix_svg as "sphinxcontrib-svg2pdfconverter" <<doc>>
     state JRE as "JRE" <<doc>> : Java Runtime Environment
@@ -407,10 +409,12 @@
     u_guide --> Sphinx
     Sphinx --> m2r
     Sphinx --> rtd_theme
+    Sphinx --> tabs
     Sphinx --> sphnix_puml
     Sphinx --> sphnix_svg
     m2r --> Python3
     rtd_theme --> Python3
+    tabs --> Python3
     sphnix_puml --> Python3
     sphnix_svg --> Python3
     Sphinx --> PlantUML