patch 8.2.4025: error for import not ending in .vim does not work for .vimrc

Problem:    Error for import not ending in .vim does not work for .vimrc.
Solution:   Check that .vim is the end. (closes #9484)
diff --git a/src/vim9script.c b/src/vim9script.c
index 81f3967..4d16a2a 100644
--- a/src/vim9script.c
+++ b/src/vim9script.c
@@ -474,10 +474,14 @@
 	    semsg(_(e_trailing_characters_str), expr_end);
 	    goto erret;
 	}
-
-	if (end == NULL)
+	if (end == NULL || end[4] != NUL)
 	{
-	    semsg(_(e_imported_script_must_end_in_dot_vim_str), p);
+	    semsg(_(e_imported_script_must_use_as_or_end_in_dot_vim_str), p);
+	    goto erret;
+	}
+	if (end == p)
+	{
+	    semsg(_(e_cannot_import_dot_vim_without_using_as), p);
 	    goto erret;
 	}
 	as_name = vim_strnsave(p, end - p);