PYTHON-4507 pip>=21.3 is required for editable installs

Author: ShaneHarvey

doc/changelog.rst

@@ -16,7 +16,7 @@ Unavoidable breaking changes
 ............................
 
 - Since we are now using ``hatch`` as our build backend, we no longer have a ``setup.py`` file
-  and require installation using ``pip``.
+  and require installation using ``pip``. ``pip`` >= 21.3 is required for editable installs.
 
 Changes in Version 4.7.3
 -------------------------

setup.py

@@ -1,5 +1,8 @@
 from __future__ import annotations
 
-msg = "PyMongo>=4.8 no longer supports building via setup.py, use python -m pip install <path/to/pymongo> instead"
+msg = (
+    "PyMongo>=4.8 no longer supports building via setup.py, use python -m pip install <path/to/pymongo> instead. If "
+    "this is an editable install (-e) please upgrade to pip>=21.3 first: python -m pip install --upgrade pip"
+)
 
 raise RuntimeError(msg)