DOC: Update a couple links to numpy source code in README.md.

Author: WarrenWeckesser

README.md

@@ -1935,9 +1935,9 @@ Here's a collection of resources for learning about the C API for ufuncs.
   However, the `distutils` subpackage of NumPy is deprecated.
 * Some relevant NumPy source code, if you want to dive deep:
   * `PyUFuncObject` along with related C types and macros are defined in
-   [`numpy/numpy/core/include/numpy/ufuncobject.h`](https://github.com/numpy/numpy/blob/7214ca4688545b432c45287195e2f46c5e418ce8/numpy/core/include/numpy/ufuncobject.h).
+   [`numpy/numpy/_core/include/numpy/ufuncobject.h`](https://github.com/numpy/numpy/blob/main/numpy/_core/include/numpy/ufuncobject.h).
   * `PyUFunc_FromFuncAndData` and `PyUFunc_FromFuncAndDataAndSignatureAndIdentity`
-    are defined in the file [`numpy/numpy/core/src/umath/ufunc_object.c`](https://github.com/numpy/numpy/blob/7214ca4688545b432c45287195e2f46c5e418ce8/numpy/core/src/umath/ufunc_object.c).
+    are defined in the file [`numpy/numpy/core/_src/umath/ufunc_object.c`](https://github.com/numpy/numpy/blob/main/numpy/_core/src/umath/ufunc_object.c).
 * Section of the [SciPy Lecture Notes](https://scipy-lectures.org/index.html) on ufuncs:
   * [2.2.2 Universal Functions](https://scipy-lectures.org/advanced/advanced_numpy/index.html#universal-functions)
 * [Data Type API](https://numpy.org/doc/stable/reference/c-api/dtype.html) --