Remove the pytest-coverage setup because we don't use it (and haven't…

… for a while) (#790)

pyproject.toml

@@ -81,28 +81,6 @@ norecursedirs = ["dist", "build", "dev", "typings"]
 addopts = ["--cov=probdiffeq", "--cov-report=html"]
 
 
-# This is how we measure coverage; it is purely an internal/local thing for now.
-# That means that we don't display test coverage, but use it to guide refactoring
-# the tests.
-
-[tool.coverage.run]
-source = ["probdiffeq/*"]
-omit = ["probdiffeq/doc_util/*"]
-
-[tool.coverage.report]
-exclude_also = [
-    # Debugging-only code should not be measured
-    "def __repr__",
-    # Interfaces should not be measured
-    "@abc.abstractmethod",
-    "raise NotImplementedError",
-    # Tree flattening/unflattening is not always called but important
-    # once functions are jitted by the user
-    "def tree_flatten",
-    "def tree_unflatten",
-    ]
-
-
 [tool.ruff]
 include = ["**.py", "**/pyproject.toml", "**.ipynb"]
 # Same as Black.