patch 9.1.1912: tests: test_plugin_comment fails

Problem:  tests: test_plugin_comment fails, because it depends on nroff
          filetype for .mom file (after v9.1.1909)
Solution: Explicitly set filetype to nroff

Signed-off-by: Christian Brabandt <[email protected]>

Author: chrisbra

src/testdir/test_plugin_comment.vim

@@ -58,7 +58,7 @@ func Test_backward_slash_uncomment()
   let input_file = "Test_backward_slash_uncomment_input.mom"
   call writefile(lines, input_file, "D")
 
-  let buf = RunVimInTerminal('-c "packadd comment" ' .. input_file, {})
+  let buf = RunVimInTerminal('-c "packadd comment" -c "set ft=nroff" ' .. input_file, {})
   call term_sendkeys(buf, "gcc")
   let output_file = "backward_slash_uncomment_test.mom"
   call term_sendkeys(buf, $":w {output_file}\<CR>")

src/version.c

@@ -729,6 +729,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1912,
 /**/
     1911,
 /**/