Remove 'sphinx.ext.duration' from the mypy whitelist (#11404)

Author: danieleades

pyproject.toml

@@ -330,7 +330,6 @@ module = [
     "sphinx.ext.autosummary",
     "sphinx.ext.autosummary.generate",
     "sphinx.ext.doctest",
-    "sphinx.ext.duration",
     "sphinx.ext.graphviz",
     "sphinx.ext.inheritance_diagram",
     "sphinx.ext.intersphinx",

sphinx/ext/duration.py

@@ -57,7 +57,7 @@ def on_source_read(app: Sphinx, docname: str, content: list[str]) -> None:
 
 def on_doctree_read(app: Sphinx, doctree: nodes.document) -> None:
     """Record a reading duration."""
-    started_at = app.env.temp_data.get('started_at')
+    started_at = app.env.temp_data['started_at']
     duration = datetime.now() - started_at
     domain = cast(DurationDomain, app.env.get_domain('duration'))
     domain.note_reading_duration(duration)