Update a header in response to cephes::cbrt leaving detail (#27)

* Update `alg.h` header for `cephes::cbrt` leaving detail

* Get cbrt from alg.h in test_cbrt.h

Author: steppi

include/xsf/alg.h

@@ -4,7 +4,7 @@
 
 namespace xsf {
 
-XSF_HOST_DEVICE inline double cbrt(double x) { return cephes::detail::cbrt(x); }
+XSF_HOST_DEVICE inline double cbrt(double x) { return cephes::cbrt(x); }
 
 XSF_HOST_DEVICE inline float cbrt(float x) { return cbrt(static_cast<double>(x)); }
 

tests/scipy_special_tests/test_cbrt.cpp

@@ -1,6 +1,6 @@
 #include "../testing_utils.h"
 
-#include <xsf/cephes/cbrt.h>
+#include <xsf/alg.h>
 
 namespace fs = std::filesystem;
 
@@ -15,7 +15,7 @@ TEST_CASE("cephes::cbrt d->d scipy_special_tests", "[cephes::cbrt][d->d][scipy_s
 
     auto x = input;
     auto [desired, fallback] = output;
-    auto out = xsf::cephes::cbrt(x);
+    auto out = xsf::cbrt(x);
     auto error = xsf::extended_relative_error(out, desired);
     tol = adjust_tolerance(tol);
     CAPTURE(x, out, desired, error, tol, fallback);