Quote extras to guard shells with glob qualifiers (#1216)

* Shells like zsh have glob qualifiers that will error if an extra
  is not quoted. While the glob qualifiers can be disabled, adding
  quotes guards against errors if people are copy-pasting or do not
  know that they can disable the behavior.
* Use single quotes for Linux/Mac and use double quotes for Windows
  to follow existing style conventions.

Author: matthewfeickert

source/guides/installing-using-pip-and-virtual-environments.rst

@@ -292,13 +292,13 @@ specifying the extra in brackets:
 
     .. code-block:: bash
 
-        python3 -m pip install requests[security]
+        python3 -m pip install 'requests[security]'
 
 .. tab:: Windows
 
     .. code-block:: bat
 
-        py -m pip install requests[security]
+        py -m pip install "requests[security]"
 
 .. _extras:
     https://setuptools.readthedocs.io/en/latest/userguide/dependency_management.html#optional-dependencies

source/tutorials/installing-packages.rst

@@ -653,17 +653,17 @@ you know publishes one, you can include it in the pip installation command:
 
     .. code-block:: bash
 
-        python3 -m pip install SomePackage[PDF]
-        python3 -m pip install SomePackage[PDF]==3.0
-        python3 -m pip install -e .[PDF]  # editable project in current directory
+        python3 -m pip install 'SomePackage[PDF]'
+        python3 -m pip install 'SomePackage[PDF]==3.0'
+        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]  # editable project in current directory
+        py -m pip install "SomePackage[PDF]"
+        py -m pip install "SomePackage[PDF]==3.0"
+        py -m pip install -e ".[PDF]"  # editable project in current directory
 
 ----