bpo-33649: Polish asyncio subprocess and sync docs (GH-9285)



Second pass for asyncio subprocess and sync docs.


https://bugs.python.org/issue33649
diff --git a/Doc/library/asyncio-subprocess.rst b/Doc/library/asyncio-subprocess.rst
index b05c236..92c081b 100644
--- a/Doc/library/asyncio-subprocess.rst
+++ b/Doc/library/asyncio-subprocess.rst
@@ -62,8 +62,7 @@
 
    The *limit* argument sets the buffer limit for :class:`StreamReader`
    wrappers for :attr:`Process.stdout` and :attr:`Process.stderr`
-   (if :attr:`subprocess.PIPE` is passed to *stdout* and *stderr*
-   arguments).
+   (if :attr:`subprocess.PIPE` is passed to *stdout* and *stderr* arguments).
 
    Return a :class:`~asyncio.subprocess.Process` instance.
 
@@ -78,15 +77,14 @@
 
    The *limit* argument sets the buffer limit for :class:`StreamReader`
    wrappers for :attr:`Process.stdout` and :attr:`Process.stderr`
-   (if :attr:`subprocess.PIPE` is passed to *stdout* and *stderr*
-   arguments).
+   (if :attr:`subprocess.PIPE` is passed to *stdout* and *stderr* arguments).
 
    Return a :class:`~asyncio.subprocess.Process` instance.
 
    See the documentation of :meth:`loop.subprocess_shell` for other
    parameters.
 
-.. note::
+.. important::
 
    It is the application's responsibility to ensure that all whitespace and
    metacharacters are quoted appropriately to avoid `shell injection
@@ -98,7 +96,8 @@
 .. note::
 
    The default event loop that asyncio is pre-configured
-   to use on **Windows** does not support subprocesses.
+   to use on **Windows** does not support subprocesses. Subprocesses are
+   available for Windows if the :class:`ProactorEventLoop` is used.
    See :ref:`Subprocess Support on Windows <asyncio-windows-subprocess>`
    for details.
 
@@ -206,7 +205,7 @@
       exception is ignored.  This condition occurs when the process
       exits before all data are written into *stdin*.
 
-      If its desired to send data to the process' *stdin*,
+      If it is desired to send data to the process' *stdin*,
       the process needs to be created with ``stdin=PIPE``.  Similarly,
       to get anything other than ``None`` in the result tuple, the
       process has to be created with ``stdout=PIPE`` and/or
@@ -265,8 +264,8 @@
       Use the :meth:`communicate` method rather than
       :attr:`process.stdin.write() <stdin>`,
       :attr:`await process.stdout.read() <stdout>` or
-      :attr:`await process.stderr.read <stderr>`
-      to avoid deadlocks due to streams pausing reading or writing
+      :attr:`await process.stderr.read <stderr>`.
+      This avoids deadlocks due to streams pausing reading or writing
       and blocking the child process.
 
    .. attribute:: pid