Merge branch '5.x' into master

Resolved merge conflicts:
    sphinx/ext/extlinks.py
    sphinx/ext/napoleon/docstring.py
    (and removed from the latter a now unused import for flake8 F401
    compliance)

.github/workflows/main.yml

@@ -5,7 +5,7 @@ on: [push, pull_request]
 jobs:
   ubuntu:
     runs-on: ubuntu-18.04
-    name: Python ${{ matrix.python }}
+    name: Python ${{ matrix.python }} (${{ matrix.docutils }})
     strategy:
       fail-fast: false
       matrix:
@@ -18,6 +18,8 @@ jobs:
           docutils: du17
         - python: "3.10"
           docutils: du18
+        - python: "3.10"
+          docutils: du19pre
         - python: "3.11-dev"
           docutils: py311