docs: fix message

and minor fix(pycord -> py-cord)

Author: janu8ry

docs/intro.rst

@@ -31,7 +31,7 @@ If you are using Windows, then the following should be used instead: ::
     py -3 -m pip install -U py-cord
 
 
-To install additional packages for speedup, run the following command: ::
+To install additional packages for speedup,  you should use ``py-cord[speed]`` instead of ``py-cord``, e.g. ::
 
 .. code:: sh
 
@@ -41,7 +41,7 @@ To install additional packages for speedup, run the following command: ::
     py -3 -m pip install -U py-cord[speed]
 
 
-To get voice support, you should use ``py-cord[voice]`` instead of ``pycord``, e.g. ::
+To get voice support, you should use ``py-cord[voice]`` instead of ``py-cord``, e.g. ::
 
     python3 -m pip install -U py-cord[voice]