Fix scrollbars in test's expected result

Author: tompng

test/reline/yamatanooroti/test_rendering.rb

@@ -1121,15 +1121,15 @@ def test_autocomplete_super_long_and_backspace
       assert_screen(<<~'EOC')
         Multiline REPL.
         prompt> Str_BX
-                Str_BX
-                Str_BXA
-                Str_BXB
-                Str_BXC
-                Str_BXD
-                Str_BXE
-                Str_BXF
-                Str_BXG
-                Str_BXH
+                Str_BX █
+                Str_BXA█
+                Str_BXB█
+                Str_BXC█
+                Str_BXD█
+                Str_BXE█
+                Str_BXF█
+                Str_BXG█
+                Str_BXH█
                 Str_BXI
                 Str_BXJ
                 Str_BXK
@@ -1173,7 +1173,7 @@ def test_dialog_narrower_than_screen_with_scrollbar
         Multiline R
         EPL.
         prompt> Sym
-        String
+        String    █
         Struct    █
         Symbol    █
         StopIterat█