patch 8.2.0780: libvterm code lags behind the upstream version

Problem:    Libvterm code lags behind the upstream version.
Solution:   Include revisions 724 - 726.
diff --git a/src/libvterm/doc/seqs.txt b/src/libvterm/doc/seqs.txt
index c26dc44..164120c 100644
--- a/src/libvterm/doc/seqs.txt
+++ b/src/libvterm/doc/seqs.txt
@@ -97,6 +97,7 @@
       CSI Z            = CBT
       CSI `            = HPA
       CSI a            = HPR
+      CSI b            = REP
 123   CSI   c          = DA, device attributes
 123       0            =   DA
  23   CSI >   c        = DECSDA