patch 8.2.0802: libvterm code lags behind the upstream version

Problem:    Libvterm code lags behind the upstream version.
Solution:   Include revisions 759 - 762.
diff --git a/src/libvterm/t/harness.c b/src/libvterm/t/harness.c
index 92882fd..fd129b7 100644
--- a/src/libvterm/t/harness.c
+++ b/src/libvterm/t/harness.c
@@ -206,7 +206,14 @@
   NULL // resize
 };
 
-// These callbacks are shared by State and Screen
+static VTermStateFallbacks fallbacks = {
+  parser_control, // control
+  parser_csi, // csi
+  parser_osc, // osc
+  parser_dcs // dcs
+};
+
+/* These callbacks are shared by State and Screen */
 
 static int want_movecursor = 0;
 static VTermPos state_pos;
@@ -319,6 +326,7 @@
   int italic;
   int blink;
   int reverse;
+  int conceal;
   int strike;
   int font;
   VTermColor foreground;
@@ -342,6 +350,9 @@
   case VTERM_ATTR_REVERSE:
     state_pen.reverse = val->boolean;
     break;
+  case VTERM_ATTR_CONCEAL:
+    state_pen.conceal = val->boolean;
+    break;
   case VTERM_ATTR_STRIKE:
     state_pen.strike = val->boolean;
     break;
@@ -552,7 +563,7 @@
           want_settermprop = sense;
           break;
         case 'f':
-          vterm_state_set_unrecognised_fallbacks(state, sense ? &parser_cbs : NULL, NULL);
+          vterm_state_set_unrecognised_fallbacks(state, sense ? &fallbacks : NULL, NULL);
           break;
         default:
           fprintf(stderr, "Unrecognised WANTSTATE flag '%c'\n", line[i]);