Fix tmux plugin

ftplugin/tmux.vim

@@ -0,0 +1,16 @@
+if exists('g:polyglot_disabled') && index(g:polyglot_disabled, 'tmux') != -1
+  finish
+endif
+
+" Vim filetype plugin file
+" Language: tmux(1) configuration file
+" URL: https://github.com/ericpruitt/tmux.vim/
+" Maintainer: Eric Pruitt <eric.pruitt@gmail.com>
+" Last Changed: 2017 Mar 10
+
+if exists("b:did_ftplugin")
+  finish
+endif
+let b:did_ftplugin = 1
+
+setlocal commentstring=#\ %s