patch 8.2.3377: Vim9: :disass completion does not understand "s:"

Problem:    Vim9: :disass completion does not understand "s:".
Solution:   Expand "s:" to a pattern. (closes #8780)
diff --git a/src/cmdexpand.c b/src/cmdexpand.c
index 362ed77..27fda78 100644
--- a/src/cmdexpand.c
+++ b/src/cmdexpand.c
@@ -2073,7 +2073,9 @@
 
     // When expanding a function name starting with s:, match the <SNR>nr_
     // prefix.
-    if (xp->xp_context == EXPAND_USER_FUNC && STRNCMP(pat, "^s:", 3) == 0)
+    if ((xp->xp_context == EXPAND_USER_FUNC
+				       || xp->xp_context == EXPAND_DISASSEMBLE)
+	    && STRNCMP(pat, "^s:", 3) == 0)
     {
 	int len = (int)STRLEN(pat) + 20;