Add support for gleam, closes #655

Co-authored-by: Jeff Kreeftmeijer <jeffkreeftmeijer@gmail.com>

ftplugin/dune.vim

@@ -2,6 +2,14 @@ if has_key(g:polyglot_is_disabled, 'ocaml')
   finish
 endif
 
+" Language:    Dune buildsystem
+" Maintainer:  Markus Mottl        <markus.mottl@gmail.com>
+"              Anton Kochkov       <anton.kochkov@gmail.com>
+" URL:         https://github.com/ocaml/vim-ocaml
+" Last Change:
+"              2018 Nov 3 - Added commentstring (Markus Mottl)
+"              2017 Sep 6 - Initial version (Etienne Millon)
+
 if exists("b:did_ftplugin")
   finish
 endif
@@ -12,3 +20,5 @@ set lisp
 " Comment string
 setl commentstring=;\ %s
 setl comments=:;
+
+setl iskeyword+=#,?,.,/

ftplugin/gleam.vim

@@ -0,0 +1,32 @@
+if has_key(g:polyglot_is_disabled, 'gleam')
+  finish
+endif
+
+
+if exists("b:did_ftplugin")
+    finish
+endif
+let b:did_ftplugin = 1
+
+compiler gleam
+
+setlocal commentstring=//%s
+setlocal formatoptions-=t formatoptions+=croqnl
+
+setlocal comments=s0:/*!,ex:*/,s1:/*,mb:*,ex:*/,:////,:///,://
+
+" j was only added in 7.3.541, so stop complaints about its nonexistence
+silent! setlocal formatoptions+=j
+
+" smartindent will be overridden by indentexpr if filetype indent is on, but
+" otherwise it's better than nothing.
+setlocal smartindent nocindent
+
+setlocal tabstop=2 shiftwidth=2 softtabstop=2 expandtab
+setlocal textwidth=79
+
+setlocal suffixesadd=.gleam
+
+augroup gleam.vim
+autocmd!
+augroup END

ftplugin/ocaml.vim

@@ -9,7 +9,7 @@ endif
 "              Pierre Vittet       <pierre-vittet@pvittet.com>
 "              Stefano Zacchiroli  <zack@bononia.it>
 "              Vincent Aravantinos <firstname.name@imag.fr>
-" URL:         http://www.ocaml.info/vim/ftplugin/ocaml.vim
+" URL:         https://github.com/ocaml/vim-ocaml
 " Last Change:
 "              2013 Oct 27 - Added commentstring (MM)
 "              2013 Jul 26 - load default compiler settings (MM)

ftplugin/sexplib.vim

@@ -2,9 +2,10 @@ if has_key(g:polyglot_is_disabled, 'ocaml')
   finish
 endif
 
+" Vim filetype plugin file
 " Language:    Sexplib
 " Maintainer:  Markus Mottl        <markus.mottl@gmail.com>
-" URL:         http://www.ocaml.info/vim/ftplugin/sexplib.vim
+" URL:         https://github.com/ocaml/vim-ocaml
 " Last Change:
 "              2017 Apr 12 - First version (MM)