Remove man plugin from vim, it does not work for nvim, closes #576

ftplugin/yaml.vim

@@ -0,0 +1,29 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'yaml') == -1
+
+" Vim filetype plugin file
+" Language:             YAML (YAML Ain't Markup Language)
+" Previous Maintainer:  Nikolai Weibull <now@bitwi.se> (inactive)
+" Last Change:      	2020 Mar 02
+
+if exists("b:did_ftplugin")
+  finish
+endif
+let b:did_ftplugin = 1
+
+let s:cpo_save = &cpo
+set cpo&vim
+
+let b:undo_ftplugin = "setl com< cms< et< fo<"
+
+setlocal comments=:# commentstring=#\ %s expandtab
+setlocal formatoptions-=t formatoptions+=croql
+
+if !exists("g:yaml_recommended_style") || g:yaml_recommended_style != 0
+  let b:undo_ftplugin .= " sw< sts<"
+  setlocal shiftwidth=2 softtabstop=2
+endif
+
+let &cpo = s:cpo_save
+unlet s:cpo_save
+
+endif