feat: stabilize disable_all_formatting

Configurations.md

@@ -521,11 +521,13 @@ fn main() {
 
 ## `disable_all_formatting`
 
-Don't reformat anything
+Don't reformat anything.
+
+Note that this option may be soft-deprecated in the future once the [ignore](#ignore) option is stabilized. Nightly toolchain users are encouraged to use [ignore](#ignore) instead when possible.
 
 - **Default value**: `false`
 - **Possible values**: `true`, `false`
-- **Stable**: No (tracking issue: #3388)
+- **Stable**: Yes
 
 ## `edition`
 

src/config/mod.rs

@@ -155,7 +155,7 @@ create_config! {
         "Require a specific version of rustfmt";
     unstable_features: bool, false, false,
             "Enables unstable features. Only available on nightly channel";
-    disable_all_formatting: bool, false, false, "Don't reformat anything";
+    disable_all_formatting: bool, false, true, "Don't reformat anything";
     skip_children: bool, false, false, "Don't reformat out of line modules";
     hide_parse_errors: bool, false, false, "Hide errors from the parser";
     error_on_line_overflow: bool, false, false, "Error if unable to get all lines within max_width";

src/test/mod.rs

@@ -469,11 +469,6 @@ fn stdin_works_with_modified_lines() {
 #[test]
 fn stdin_disable_all_formatting_test() {
     init_log();
-    match option_env!("CFG_RELEASE_CHANNEL") {
-        None | Some("nightly") => {}
-        // These tests require nightly.
-        _ => return,
-    }
     let input = String::from("fn main() { println!(\"This should not be formatted.\"); }");
     let mut child = Command::new(rustfmt().to_str().unwrap())
         .stdin(Stdio::piped())