terraform-fmt: add page (#3958)

pages/common/terraform-fmt.md

@@ -0,0 +1,20 @@
+# terraform fmt
+
+> Format configuration according to Terraform language style conventions.
+> More information: <https://www.terraform.io/docs/commands/fmt.html>.
+
+- Format the configuration in the current directory:
+
+`terraform fmt`
+
+- Format the configuration in the current directory and subdirectories:
+
+`terraform fmt -recursive`
+
+- Display diffs of formatting changes:
+
+`terraform fmt -diff`
+
+- Do not list files that were formatted to stdout:
+
+`terraform fmt -list=false`