Add ansible filetype detection

Based on 86eea3d684

templates/nvim/lua/filetype.lua.j2

@@ -0,0 +1,40 @@
+local ansible_keywords = {
+  'hosts',
+  'tasks',
+  'vars',
+  'vars_files',
+  'vars_prompt',
+  'handlers',
+  'roles',
+  'import_tasks',
+  'import_playbook',
+  'import_role',
+}
+
+vim.filetype.add {
+  pattern = {
+    ['playbook*.y(a?)ml'] = 'yaml.ansible',
+    ['site*.y(a?)ml'] = 'yaml.ansible',
+    ['inventory*.y(a?)ml'] = 'yaml.ansible',
+    ['task*.y(a?)ml'] = 'yaml.ansible',
+    ['requirement*.y(a?)ml'] = 'yaml.ansible',
+
+
+    ['.*/tasks/.*.y(a?)ml'] = 'yaml.ansible',
+    ['.*/vars/.*.y(a?)ml'] = 'yaml.ansible',
+    ['.*/playbooks/.*.y(a?)ml'] = 'yaml.ansible',
+
+    ['*.ansible.y(a?)ml'] = 'yaml.ansible',
+
+    ['.*.y(a?)ml'] = {
+      function(path, bufnr)
+        local content = vim.api.nvim_buf_get_lines(bufnr, 0, 1, false)[1] or ''
+
+        for _, keyword in pairs(ansible_keywords) do
+          local pattern = string.format('^- %s:', keyword)
+          if content:match(pattern) then return 'yaml.ansible' end
+        end
+      end,
+    },
+  },
+}