patch 8.2.3637: typos in test files

Problem:    Typos in test files.
Solution:   Correct the typos. (Dominique Pellé, closes #9175)
diff --git a/src/testdir/test_textobjects.vim b/src/testdir/test_textobjects.vim
index 16070b1..debbfb3 100644
--- a/src/testdir/test_textobjects.vim
+++ b/src/testdir/test_textobjects.vim
@@ -205,7 +205,7 @@
   normal 0f<vitsaaa
   call assert_equal('aaa', getline(1))
 
-  " selecting a tag block in an non-empty blank line should fail
+  " selecting a tag block in a non-empty blank line should fail
   call setline(1, '    ')
   call assert_beeps('normal $vaty')