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_substitute.vim b/src/testdir/test_substitute.vim
index 1c23f8c..d84daa7 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -1,6 +1,6 @@
 " Tests for multi-line regexps with ":s".
 
-function! Test_multiline_subst()
+func Test_multiline_subst()
   enew!
   call append(0, ["1 aa",
 	      \ "bb",
@@ -38,9 +38,9 @@
   call assert_equal('7x7f', getline(12))
   call assert_equal('xxxxx', getline(13))
   enew!
-endfunction
+endfunc
 
-function! Test_substitute_variants()
+func Test_substitute_variants()
   " Validate that all the 2-/3-letter variants which embed the flags into the
   " command name actually work.
   enew!
@@ -105,7 +105,7 @@
       call assert_equal(var.exp, getline('.'), msg)
     endfor
   endfor
-endfunction
+endfunc
 
 func Test_substitute_repeat()
   " This caused an invalid memory access.
@@ -401,9 +401,9 @@
 
   " List entry format: [input, cmd, output]
   let tests = [ ['aAa', "s/A/\\=substitute(submatch(0), '.', '\\', '')/",
-	      \ 			['a\a']],
+	      \				['a\a']],
 	      \ ['bBb', "s/B/\\=substitute(submatch(0), '.', '\\', '')/",
-	      \   			['b\b']],
+	      \				['b\b']],
 	      \ ['cCc', "s/C/\\=substitute(submatch(0), '.', '\<C-V>\<C-M>', '')/",
 	      \				["c\<C-V>", 'c']],
 	      \ ['dDd', "s/D/\\=substitute(submatch(0), '.', '\\\<C-V>\<C-M>', '')/",