This reverts commit e1ae63dd.

Streamline __Pyx_PySet_Remove() helper function. Add comments about unclean return values of new helper functions.
Closes #2042.

Issue #2042: add optimized versions of `x in set`, set.remove() and set.discard()

Allow overriding the extension module name in cythonize() by setting an explicit name in the Extension() object.
Closes #2038.

Reduce complexity by avoiding to redefine a helper function inside a loop that does not depend on the loop state

https://bugs.python.org/issue32240

Allow @final class decorator in pure mode. Was previously rejected for Python classes with an @cclass decorator.
Closes #2040.

Closes #2035.

But at least detect and disallow duplicate keyword arguments to parallel() and prange().

Always coerce Python arguments as "num_threads" in parallel sections to C integers, also to catch some coercion problems at compile time.

Closes #1957.

Fix types of values in libc.limits

Closes #1848.

Improve typing doc

Closes #2019.

Verbatim C code using docstring syntax.

Rewrite memoryview[i][j] and similar obvious cases into the faster memoryview[i, j]