patch 8.1.0880: MS-Windows: inconsistent selection of winpty/conpty

Problem:    MS-Windows: inconsistent selection of winpty/conpty.
Solution:   Name option 'termwintype', use ++type argument and "term_pty" for
            term_start(). (Hirohito Higashi, closes #3915)
diff --git a/runtime/doc/quickref.txt b/runtime/doc/quickref.txt
index 03ac357..75f400f 100644
--- a/runtime/doc/quickref.txt
+++ b/runtime/doc/quickref.txt
@@ -1,4 +1,4 @@
-*quickref.txt*  For Vim version 8.1.  Last change: 2018 Apr 18
+*quickref.txt*  For Vim version 8.1.  Last change: 2019 Feb 08
 
 
 		  VIM REFERENCE MANUAL    by Bram Moolenaar
@@ -930,6 +930,7 @@
 'termwinkey'	  'twk'	    key that precedes a Vim command in a terminal
 'termwinscroll'   'twsl'    max number of scrollback lines in a terminal window
 'termwinsize'	  'tws'	    size of a terminal window
+'termwintype'	  'twt'	    MS-Windows: type of pty to use for terminal window
 'terse'			    shorten some messages
 'textauto'	  'ta'	    obsolete, use 'fileformats'
 'textmode'	  'tx'	    obsolete, use 'fileformat'