Merge branch '3.9' into backport-2bd9f9b-3.9

Author: encukou

.github/workflows/doc.yml

@@ -36,7 +36,9 @@ jobs:
     - name: 'Build documentation'
       run: xvfb-run make -C Doc/ PYTHON=../python SPHINXOPTS="-q -W -j4" doctest suspicious html
     - name: 'Upload'
-      uses: actions/upload-artifact@v3
+      uses: actions/upload-artifact@v4
       with:
         name: doc-html
         path: Doc/build/html
+        include-hidden-files: true
+        overwrite: true

.readthedocs.yml

@@ -3,6 +3,8 @@
 # clicking on the docs preview link on a PR will result in a 404.
 version: 2
 formats: []
+sphinx:
+  configuration: Doc/conf.py
 build:
   os: "ubuntu-22.04"
   tools:

Doc/tutorial/classes.rst

@@ -325,7 +325,7 @@ Now what can we do with instance objects?  The only operations understood by
 instance objects are attribute references.  There are two kinds of valid
 attribute names: data attributes and methods.
 
-*data attributes* correspond to "instance variables" in Smalltalk, and to "data
+*Data attributes* correspond to "instance variables" in Smalltalk, and to "data
 members" in C++.  Data attributes need not be declared; like local variables,
 they spring into existence when they are first assigned to.  For example, if
 ``x`` is the instance of :class:`MyClass` created above, the following piece of