chore: reformat sphinx configuration

Format the configuration file to follow our coding guidelines and common
Python style conventions.

Change-Id: Ic83372287db08df0662f562f7683a02ddff0bac8
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/docs/conf.py b/docs/conf.py
index 371632a..4e8ac49 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #
-# Copyright (c) 2019-2021, Arm Limited. All rights reserved.
+# Copyright (c) 2019-2023, Arm Limited. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -13,23 +13,23 @@
 
 # -- Project information -----------------------------------------------------
 
-project = 'Trusted Firmware-A'
+project = "Trusted Firmware-A"
 
 # -- General configuration ---------------------------------------------------
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom
 # ones.
-extensions = ['myst_parser', 'sphinx.ext.autosectionlabel', 'sphinxcontrib.plantuml']
+extensions = ["myst_parser", "sphinx.ext.autosectionlabel", "sphinxcontrib.plantuml"]
 
 # Add any paths that contain templates here, relative to this directory.
-templates_path = ['_templates']
+templates_path = ["_templates"]
 
 # The suffix(es) of source filenames.
-source_suffix = ['.md', '.rst']
+source_suffix = [".md", ".rst"]
 
 # The master toctree document.
-master_doc = 'index'
+master_doc = "index"
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -45,15 +45,15 @@
 exclude_patterns = [".env", "env", ".venv", "venv"]
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = "sphinx"
 
 # Load the contents of the global substitutions file into the 'rst_prolog'
 # variable. This ensures that the substitutions are all inserted into each page.
-with open('global_substitutions.txt', 'r') as subs:
-  rst_prolog = subs.read()
+with open("global_substitutions.txt", "r") as subs:
+    rst_prolog = subs.read()
 
 # Minimum version of sphinx required
-needs_sphinx = '2.0'
+needs_sphinx = "2.0"
 
 # -- Options for HTML output -------------------------------------------------
 
@@ -68,21 +68,21 @@
 html_theme = "sphinx_rtd_theme"
 
 # The logo to display in the sidebar
-html_logo = 'resources/TrustedFirmware-Logo_standard-white.png'
+html_logo = "resources/TrustedFirmware-Logo_standard-white.png"
 
 # Options for the "sphinx-rtd-theme" theme
 html_theme_options = {
-    'collapse_navigation': False, # Can expand and collapse sidebar entries
-    'prev_next_buttons_location': 'both', # Top and bottom of the page
-    'style_external_links': True # Display an icon next to external links
+    "collapse_navigation": False,  # Can expand and collapse sidebar entries
+    "prev_next_buttons_location": "both",  # Top and bottom of the page
+    "style_external_links": True,  # Display an icon next to external links
 }
 
 # Path to _static directory
-html_static_path = ['_static']
+html_static_path = ["_static"]
 
 # Path to css file relative to html_static_path
 html_css_files = [
-    'css/custom.css',
+    "css/custom.css",
 ]
 
 # -- Options for autosectionlabel --------------------------------------------
@@ -92,4 +92,4 @@
 
 # -- Options for plantuml ----------------------------------------------------
 
-plantuml_output_format = 'svg_img'
+plantuml_output_format = "svg_img"