Add syntax files from upstream vim repository

ftplugin/go.vim

@@ -0,0 +1,22 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim filetype plugin file
+" Language:	Go
+" Maintainer:	David Barnett (https://github.com/google/vim-ft-go)
+" Last Change:	2014 Aug 16
+
+if exists('b:did_ftplugin')
+  finish
+endif
+let b:did_ftplugin = 1
+
+setlocal formatoptions-=t
+
+setlocal comments=s1:/*,mb:*,ex:*/,://
+setlocal commentstring=//\ %s
+
+let b:undo_ftplugin = 'setl fo< com< cms<'
+
+" vim: sw=2 sts=2 et
+
+endif