Quick pydoc update to smtplib.py (GH-22292)

Fixing minor mistake in the quotes around a couple of arguments for the constructor of the class `SMTP`, in smtplib.py.
diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index 0317248..bfba5c8 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -231,8 +231,8 @@ def __init__(self, host='', port=0, local_hostname=None,
                  source_address=None):
         """Initialize a new instance.
 
-        If specified, `host' is the name of the remote host to which to
-        connect.  If specified, `port' specifies the port to which to connect.
+        If specified, `host` is the name of the remote host to which to
+        connect.  If specified, `port` specifies the port to which to connect.
         By default, smtplib.SMTP_PORT is used.  If a host is specified the
         connect method is called, and if it returns anything other than a
         success code an SMTPConnectError is raised.  If specified,