patch 8.2.1025: tabpage menu and tabline not sufficiently tested

Problem:    Tabpage menu and tabline not sufficiently tested.
Solution:   Add tests. (Yegappan Lakshmanan, closes #6307)
diff --git a/src/testdir/test_digraph.vim b/src/testdir/test_digraph.vim
index f73ed7c..12162b4 100644
--- a/src/testdir/test_digraph.vim
+++ b/src/testdir/test_digraph.vim
@@ -503,7 +503,7 @@
   call delete('Xkeymap')
 endfunc
 
-" Test for the characters displayed one the screen when entering a digraph
+" Test for the characters displayed on the screen when entering a digraph
 func Test_entering_digraph()
   CheckRunVimInTerminal
   let buf = RunVimInTerminal('', {'rows': 6})