patch 9.0.0828: various typos

Problem:    Various typos.
Solution:   Correct typos. (closes #11432)
diff --git a/src/testdir/test_termcodes.vim b/src/testdir/test_termcodes.vim
index 0b2365e..8715ebf 100644
--- a/src/testdir/test_termcodes.vim
+++ b/src/testdir/test_termcodes.vim
@@ -1222,7 +1222,7 @@
   call assert_equal(5, col("'<"))
   call assert_equal(12, col("'>"))
 
-  " Multi-line selection. Right click inside thse selection.
+  " Multi-line selection. Right click inside the selection.
   call setline(1, repeat(['aaaaaa'], 7))
   call test_setmouse(3, 1)
   exe "normal ggVG\<RightMouse>y"