patch 8.2.4135: Vim9: ":scriptnames" shows unloaded imported autoload script

Problem:    Vim9: ":scriptnames" shows unloaded imported autoload script.
Solution:   Mark the unloaded script with "A". (closes #9552)
diff --git a/runtime/doc/repeat.txt b/runtime/doc/repeat.txt
index 8ea1958..067234a 100644
--- a/runtime/doc/repeat.txt
+++ b/runtime/doc/repeat.txt
@@ -380,6 +380,9 @@
 :scr[iptnames]		List all sourced script names, in the order they were
 			first sourced.  The number is used for the script ID
 			|<SID>|.
+			For a script that was used with `import autoload` but
+			was not actually sourced yet an "A" is shown after the
+			script ID.
 			{not available when compiled without the |+eval|
 			feature}