patch 9.0.0559: timer test may get stuck at hit-enter prompt

Problem:    Timer test may get stuck at hit-enter prompt.
Solution:   Feed some more characters.
diff --git a/src/testdir/test_timers.vim b/src/testdir/test_timers.vim
index 2625013..de72c78 100644
--- a/src/testdir/test_timers.vim
+++ b/src/testdir/test_timers.vim
@@ -379,11 +379,13 @@
     let a = {'foo', 'bar'}
   endfunc
   func FeedChar(id)
-    call feedkeys('x', 't')
+    call feedkeys(":\<CR>", 't')
   endfunc
   call timer_start(300, 'FeedChar')
   call timer_start(100, 'CauseAnError')
-  let x = getchar()
+  let x = getchar()   " wait for error in timer
+  let x = getchar(0)  " read any remaining chars
+  let x = getchar(0)
 
   set ut&
   call test_override('no_wait_return', 1)
diff --git a/src/version.c b/src/version.c
index 48f2ca5..7b4e24f 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    559,
+/**/
     558,
 /**/
     557,