Refs #30948 -- Updated install instructions to use pip instead of setup.py.

Co-authored-by: Nick Pope <nick.pope@flightdataservices.com>

INSTALL

@@ -3,8 +3,6 @@ Thanks for downloading Django.
 To install it, make sure you have Python 3.6 or greater installed. Then run
 this command from the command prompt:
 
-    python setup.py install
-
-If you're upgrading from a previous version, you need to remove it first.
+    python -m pip install .
 
 For more detailed instructions, see docs/intro/install.txt.

docs/faq/troubleshooting.txt

@@ -14,9 +14,9 @@ Problems running ``django-admin``
 -----------------------------------
 
 :doc:`django-admin </ref/django-admin>` should be on your system path if you
-installed Django via ``python setup.py``. If it's not on your path, you can
-find it in ``site-packages/django/bin``, where ``site-packages`` is a directory
-within your Python installation. Consider symlinking to :doc:`django-admin
+installed Django via ``pip``. If it's not on your path, you can find it in
+``site-packages/django/bin``, where ``site-packages`` is a directory within
+your Python installation. Consider symlinking to :doc:`django-admin
 </ref/django-admin>` from some place on your path, such as
 :file:`/usr/local/bin`.
 

docs/ref/django-admin.txt

@@ -11,8 +11,8 @@ does the same thing as ``django-admin`` but also sets the
 project's ``settings.py`` file.
 
 The ``django-admin`` script should be on your system path if you installed
-Django via its ``setup.py`` utility. If it's not on your path, you can find it
-in ``site-packages/django/bin`` within your Python installation. Consider
+Django via ``pip``. If it's not on your path, you can find it in
+``site-packages/django/bin`` within your Python installation. Consider
 symlinking it from some place on your path, such as ``/usr/local/bin``.
 
 For Windows users, who do not have symlinking functionality available, you can