Add HCL configuration formatting builtin support

lua/null-ls/builtins/formatting/hclfmt.lua

@@ -0,0 +1,19 @@
+local h = require("null-ls.helpers")
+local methods = require("null-ls.methods")
+
+local FORMATTING = methods.internal.FORMATTING
+
+return h.make_builtin({
+    name = "hclfmt",
+    meta = {
+        url = "https://github.com/fatih/hclfmt",
+        description = "Formatter for HCL configuration files",
+    },
+    method = FORMATTING,
+    filetypes = { "hcl" },
+    generator_opts = {
+        command = "hclfmt",
+        to_stdin = true,
+    },
+    factory = h.formatter_factory,
+})