🧪🎨 Enforce empty trivial change notes

This is what the contribution document is asking for but the
automation never checked really. Which led to contributors filling
out trivial changelog entries without realizing that they are never
published.

The patch corrects that and relocates the violating change notes to
better sections.

.pre-commit-config.yaml

@@ -104,6 +104,34 @@ repos:
     types_or:
     - file
     - symlink
+  - id: trivial-news-fragment-empty
+    name: Trivial NEWS fragments must be empty
+    language: python
+    entry: >-
+      python3 -Ic 'import pathlib, sys;
+      trivial_notes = map(pathlib.Path, sys.argv[1:]);
+
+      non_empty_notes = [
+        note for note in trivial_notes
+        if note.lstat().st_size
+      ];
+      some_notes_are_non_empty = bool(len(non_empty_notes));
+
+      some_notes_are_non_empty or sys.exit(0);
+
+      print(f"ERROR: the following change log fragments must be empty:");
+
+      print("\n\t* ".join(["", *map(str, non_empty_notes)]));
+
+      print();
+
+      sys.exit(1)
+      '
+    files: ^news/[^.]+\.trivial.*$
+    types: []
+    types_or:
+    - file
+    - symlink
 
 ci:
   autofix_prs: false

news/12854.contrib.rst

@@ -0,0 +1,2 @@
+The pre-commit linting suite now makes sure that any change
+notes labeled as ``trivial`` are empty.

news/setuptools.vendor.rst

@@ -1 +1,4 @@
 Upgrade setuptools to 70.3.0
+
+Additionally, remove the suppressed deprecation warning from the vendored
+``pkg_resources`` copy to ensure builds succeed with ``PYTHONWARNINGS=error``.