fix grammar issues with style guide

Author: thomasballinger

docs/writing/style.rst

@@ -128,7 +128,7 @@ called with each recipient as an argument: ``send('Hello', 'God', 'Mom',
 'Cthulhu')``, and in the function body ``args`` will be equal to ``('God',
 'Mom', 'Cthulhu')``.
 
-However, this construct has some drawback and should be used with caution. If a
+However, this construct has some drawbacks and should be used with caution. If a
 function receives a list of arguments of the same nature, it is often more
 clear to define it as a function of one argument, that argument being a list or
 any sequence. Here, if ``send`` has multiple recipients, it is better to define
@@ -156,7 +156,7 @@ Python functions that are:
 
 * easy to read (the name and arguments need no explanations)
 
-* easy to change (adding a new keyword argument do not break other parts of the
+* easy to change (adding a new keyword argument does not break other parts of the
   code)
 
 Avoid the magical wand
@@ -179,7 +179,7 @@ way.  However, knowing how to use them and particularly when **not** to use
 them is the most important.
 
 Like a Kungfu master, a Pythonista knows how to kill with a single finger, and
-never do it.
+never to do it.
 
 We are all consenting adults
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~