patch 7.4.1894

Problem:    Cannot get the window ID for a mouse click.
Solution:   Add v:mouse_winid.

src/version.c

@@ -753,6 +753,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1894,
 /**/
     1893,
 /**/