add traceback to sphinx build output

Author: rmorshea

noxfile.py

@@ -130,8 +130,8 @@ def test_docs(session: Session) -> None:
     """Verify that the docs build and that doctests pass"""
     install_requirements_file(session, "build-docs")
     install_idom_dev(session, extras="all")
-    session.run("sphinx-build", "-b", "html", "docs/source", "docs/build")
-    session.run("sphinx-build", "-b", "doctest", "docs/source", "docs/build")
+    session.run("sphinx-build", "-T", "-b", "html", "docs/source", "docs/build")
+    session.run("sphinx-build", "-T", "-b", "doctest", "docs/source", "docs/build")
 
 
 @nox.session