Quotes may be needed on macOS

Co-authored-by: Andrew Murray <[email protected]>

Author: hugovk

docs/releasenotes/9.1.0.rst

@@ -38,6 +38,9 @@ For example:
     # Or for all:
     python3 -m pip install .[docs,tests]
 
+On macOS, the last argument may need to be wrapped in quotes, e.g.
+``python3 -m pip install ".[tests]"``
+
 Therefore ``requirements.txt`` has been removed along with the ``make install-req``
 command for installing its contents.