Add syntax files from upstream vim repository

indent/go.vim

@@ -1,3 +1,73 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'vim') == -1
+  
+" Vim indent file
+" Language:	Go
+" Maintainer:	David Barnett (https://github.com/google/vim-ft-go)
+" Last Change:	2017 Jun 13
+"
+" TODO:
+" - function invocations split across lines
+" - general line splits (line ends in an operator)
+
+if exists('b:did_indent')
+  finish
+endif
+let b:did_indent = 1
+
+" C indentation is too far off useful, mainly due to Go's := operator.
+" Let's just define our own.
+setlocal nolisp
+setlocal autoindent
+setlocal indentexpr=GoIndent(v:lnum)
+setlocal indentkeys+=<:>,0=},0=)
+
+if exists('*GoIndent')
+  finish
+endif
+
+function! GoIndent(lnum)
+  let l:prevlnum = prevnonblank(a:lnum-1)
+  if l:prevlnum == 0
+    " top of file
+    return 0
+  endif
+
+  " grab the previous and current line, stripping comments.
+  let l:prevl = substitute(getline(l:prevlnum), '//.*$', '', '')
+  let l:thisl = substitute(getline(a:lnum), '//.*$', '', '')
+  let l:previ = indent(l:prevlnum)
+
+  let l:ind = l:previ
+
+  if l:prevl =~ '[({]\s*$'
+    " previous line opened a block
+    let l:ind += shiftwidth()
+  endif
+  if l:prevl =~# '^\s*\(case .*\|default\):$'
+    " previous line is part of a switch statement
+    let l:ind += shiftwidth()
+  endif
+  " TODO: handle if the previous line is a label.
+
+  if l:thisl =~ '^\s*[)}]'
+    " this line closed a block
+    let l:ind -= shiftwidth()
+  endif
+
+  " Colons are tricky.
+  " We want to outdent if it's part of a switch ("case foo:" or "default:").
+  " We ignore trying to deal with jump labels because (a) they're rare, and
+  " (b) they're hard to disambiguate from a composite literal key.
+  if l:thisl =~# '^\s*\(case .*\|default\):$'
+    let l:ind -= shiftwidth()
+  endif
+
+  return l:ind
+endfunction
+
+" vim: sw=2 sts=2 et
+
+endif
 if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'go') == -1
   
 " Copyright 2011 The Go Authors. All rights reserved.