eval: implement timers. vim-patch: 7.4.1578, 7.4.1831

For the moment, timers are triggered during sleep,
but not in wait-for-input modes, like press-RETURN or f_getchar()

src/nvim/version.c

@@ -70,6 +70,7 @@ static char *features[] = {
 // clang-format off
 static int included_patches[] = {
   1832,
+  1831,
   1809,
   1808,
   1806,
@@ -82,6 +83,7 @@ static int included_patches[] = {
   1652,
   1643,
   1641,
+  // 1624 NA
 
   // 1600 NA
   // 1599 NA
@@ -106,7 +108,7 @@ static int included_patches[] = {
   // 1581,
   // 1580,
   // 1579,
-  // 1578,
+  1578,
   // 1577,
   1576,
   // 1575 NA