Run coverage tool on Python 3.14 to parse PEP 758 except syntax

Author: adamtheturtle

.github/workflows/test.yml

@@ -300,7 +300,9 @@ jobs:
       - name: Require 100% Coverage
         id: coverage
         run: |
-          uv tool install 'coverage[toml]'
+          # Pin to 3.14 so ``coverage`` can parse source files that use
+          # PEP 758 syntax (parenthesis-free ``except E1, E2:``).
+          uv tool install --python 3.14 'coverage[toml]'
 
           coverage combine
           coverage html --skip-covered --skip-empty