Fix invalid command

Author: dukecat0

source/tutorials/installing-packages.rst

@@ -653,15 +653,15 @@ Install `setuptools extras`_.
 
         python3 -m pip install SomePackage[PDF]
         python3 -m pip install SomePackage[PDF]==3.0
-        python3 -m pip install -e .[PDF]==3.0  # editable project in current directory
+        python3 -m pip install -e .[PDF]  # editable project in current directory
 
 .. tab:: Windows
 
     .. code-block:: bat
 
         py -m pip install SomePackage[PDF]
         py -m pip install SomePackage[PDF]==3.0
-        py -m pip install -e .[PDF]==3.0  # editable project in current directory
+        py -m pip install -e .[PDF]  # editable project in current directory
 
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