Redo of PR#5345. Fixed spelling and typographical errors found by CodeSpell.

Signed-off-by: Shaun Case <warmsocks@gmail.com>
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/library/ssl_tls12_server.c b/library/ssl_tls12_server.c
index a1505d1..590c874 100644
--- a/library/ssl_tls12_server.c
+++ b/library/ssl_tls12_server.c
@@ -1261,7 +1261,7 @@
      * Handshake layer:
      *     0  .   0   handshake type
      *     1  .   3   handshake length
-     *     4  .   5   DTLS only: message seqence number
+     *     4  .   5   DTLS only: message sequence number
      *     6  .   8   DTLS only: fragment offset
      *     9  .  11   DTLS only: fragment length
      */