patch 8.1.0711: test files still use function!

Problem:    Test files still use function!.
Solution:   Remove the exclamation mark.  Fix overwriting a function.
diff --git a/src/testdir/test_textobjects.vim b/src/testdir/test_textobjects.vim
index 6a2f504..3c403ab 100644
--- a/src/testdir/test_textobjects.vim
+++ b/src/testdir/test_textobjects.vim
@@ -236,7 +236,7 @@
   %delete _
 endfunc
 
-func! Test_sentence_with_cursor_on_delimiter()
+func Test_sentence_with_cursor_on_delimiter()
   enew!
   call setline(1, "A '([sentence.])'  A sentence.")