[4.0.x] Bumped minimum Sphinx version to 4.5.0.

Related Sphinx changes:
- https://github.com/sphinx-doc/sphinx/pull/8898
- https://github.com/sphinx-doc/sphinx/issues/8326
Backport of ebf25555bb from main

docs/conf.py

@@ -32,7 +32,7 @@ sys.path.append(abspath(join(dirname(__file__), "_ext")))
 # -- General configuration -----------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = "1.6.0"
+needs_sphinx = "4.5.0"
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
@@ -94,8 +94,8 @@ source_suffix = ".txt"
 # The encoding of source files.
 # source_encoding = 'utf-8-sig'
 
-# The master toctree document.
-master_doc = "contents"
+# The root toctree document.
+root_doc = "contents"
 
 # General substitutions.
 project = "Django"
@@ -127,12 +127,12 @@ else:
 django_next_version = "4.1"
 
 extlinks = {
-    "bpo": ("https://bugs.python.org/issue?@action=redirect&bpo=%s", "bpo-"),
-    "commit": ("https://github.com/django/django/commit/%s", ""),
-    "cve": ("https://nvd.nist.gov/vuln/detail/CVE-%s", "CVE-"),
+    "bpo": ("https://bugs.python.org/issue?@action=redirect&bpo=%s", "bpo-%s"),
+    "commit": ("https://github.com/django/django/commit/%s", "%s"),
+    "cve": ("https://nvd.nist.gov/vuln/detail/CVE-%s", "CVE-%s"),
     # A file or directory. GitHub redirects from blob to tree if needed.
-    "source": ("https://github.com/django/django/blob/main/%s", ""),
-    "ticket": ("https://code.djangoproject.com/ticket/%s", "#"),
+    "source": ("https://github.com/django/django/blob/main/%s", "%s"),
+    "ticket": ("https://code.djangoproject.com/ticket/%s", "#%s"),
 }
 
 # The language for content autogenerated by Sphinx. Refer to documentation
@@ -337,7 +337,7 @@ man_pages = [
 # description, category, toctree_only)
 texinfo_documents = [
     (
-        master_doc,
+        root_doc,
         "django",
         "",
         "",