tests: Increase minimum pymdown-extensions version required

devdeps.txt

@@ -10,7 +10,7 @@ twine>=5.1; python_version < '3.13'
 duty>=1.4
 ruff>=0.4
 pygments>=2.16
-pymdown-extensions>=10.0
+pymdown-extensions>=10.7
 pytest>=8.2
 pytest-cov>=5.0
 pytest-randomly>=3.15