Link to blurb on PyPI in the NEWS.d READMEs. (#3323)

Misc/NEWS.d/next/Build/README.rst

-Put news entry ``blurb`` files for the *Build* section in this directory.
+Put news entry `blurb`_ files for the *Build* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/C API/README.rst

-Put news entry ``blurb`` files for the *C API* section in this directory.
+Put news entry `blurb`_ files for the *C API* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Core and Builtins/README.rst

-Put news entry ``blurb`` files for the *Core and Builtins* section in this directory.
+Put news entry `blurb`_ files for the *Core and Builtins* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Documentation/README.rst

-Put news entry ``blurb`` files for the *Documentation* section in this directory.
+Put news entry `blurb`_ files for the *Documentation* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/IDLE/README.rst

-Put news entry ``blurb`` files for the *IDLE* section in this directory.
+Put news entry `blurb`_ files for the *IDLE* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Library/README.rst

-Put news entry ``blurb`` files for the *Library* section in this directory.
+Put news entry `blurb`_ files for the *Library* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Security/README.rst

-Put news entry ``blurb`` files for the *Security* section in this directory.
+Put news entry `blurb`_ files for the *Security* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Tests/README.rst

-Put news entry ``blurb`` files for the *Tests* section in this directory.
+Put news entry `blurb`_ files for the *Tests* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Tools-Demos/README.rst

-Put news entry ``blurb`` files for the *Tools/Demos* section in this directory.
+Put news entry `blurb`_ files for the *Tools/Demos* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/Windows/README.rst

-Put news entry ``blurb`` files for the *Windows* section in this directory.
+Put news entry `blurb`_ files for the *Windows* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/

Misc/NEWS.d/next/macOS/README.rst

-Put news entry ``blurb`` files for the *macOS* section in this directory.
+Put news entry `blurb`_ files for the *macOS* section in this directory.
+
+.. _blurb: https://pypi.org/project/blurb/