patch 8.2.0795: libvterm code lags behind the upstream version

Problem:    Libvterm code lags behind the upstream version.
Solution:   Include revisions 748 - 754.
diff --git a/src/libvterm/t/62screen_damage.test b/src/libvterm/t/62screen_damage.test
index 791a96c..32cac2d 100644
--- a/src/libvterm/t/62screen_damage.test
+++ b/src/libvterm/t/62screen_damage.test
@@ -1,5 +1,5 @@
 INIT
-WANTSCREEN Db
+WANTSCREEN aDb
 
 !Putglyph
 RESET
@@ -152,4 +152,4 @@
 DAMAGEFLUSH
   moverect 1..25,0..80 -> 0..24,0..80
   damage 24..25,0..80
-  ?screen_chars 23,0,24,5 = 0x41,0x42,0x45
+  ?screen_chars 23,0,24,5 = "ABE"