patch 9.0.0253: a symlink to an autoload script results in two entries

Problem:    A symlink to an autoload script results in two entries in the list
            of scripts, items expected in one are actually in the other.
Solution:   Have one script item refer to the actually sourced one.
            (closes #10960)

runtime/doc/repeat.txt

@@ -417,6 +417,10 @@ For writing a Vim script, see chapter 41 of the user manual |usr_41.txt|.
 			For a script that was used with `import autoload` but
 			was not actually sourced yet an "A" is shown after the
 			script ID.
+			For a script that was referred to by one name but
+			after resolving symbolic links got sourced with
+			another name the other script is after "->".  E.g.
+			"20->22" means script 20 was sourced as script 22.
 			{not available when compiled without the |+eval|
 			feature}