Don't tmux pipe-pane if efm targets \r or \e

If the user cares about these special characters, make sure the captured
output is identical to the other adapters.

autoload/dispatch/tmux.vim

@@ -33,7 +33,8 @@ function! dispatch#tmux#handle(request) abort
 endfunction
 
 function! dispatch#tmux#make(request) abort
-  let pipepane = &shellpipe ==# '2>&1| tee' || &shellpipe ==# '|& tee'
+  let pipepane = (&shellpipe ==# '2>&1| tee' || &shellpipe ==# '|& tee')
+        \ && a:request.format !~# '%\\[er]'
   let session = get(g:, 'tmux_session', '')
   let script = dispatch#isolate(['TMUX', 'TMUX_PANE'],
         \ call('dispatch#prepare_make',