vim-patch:8.1.2053: SafeStateAgain not triggered if callback uses feedkeys()

Problem:    SafeStateAgain not triggered if callback uses feedkeys().
Solution:   Check for safe state in the input loop.  Make log messages easier
            to find. Add 'S' flag to state().

d103ee7843

Include misc1.c change from patch 8.1.2062.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/getchar.c

@@ -885,7 +885,7 @@ int ins_typebuf(char *str, int noremap, int offset, bool nottyped, bool silent)
   if (++typebuf.tb_change_cnt == 0) {
     typebuf.tb_change_cnt = 1;
   }
-  state_no_longer_safe();
+  state_no_longer_safe("ins_typebuf()");
 
   addlen = (int)strlen(str);
 
@@ -1629,7 +1629,7 @@ int vgetc(void)
   // Need to process the character before we know it's safe to do something
   // else.
   if (c != K_IGNORE) {
-    state_no_longer_safe();
+    state_no_longer_safe("key typed");
   }
 
   return c;