cli: migrate ui.write_hint() to writeln!()

src/cli_util.rs

@@ -1089,11 +1089,11 @@ pub fn print_failed_git_export(
             formatter.write_str("\n")?;
         }
         drop(formatter);
-        ui.write_hint(
+        writeln!(
+            ui.hint(),
             r#"Hint: Git doesn't allow a branch name that looks like a parent directory of
 another (e.g. `foo` and `foo/bar`). Try to rename the branches that failed to
-export or their "parent" branches.
-"#,
+export or their "parent" branches."#,
         )?;
     }
     Ok(())
@@ -1724,7 +1724,7 @@ pub fn handle_command_result(ui: &mut Ui, result: Result<(), CommandError>) -> i
         Err(CommandError::UserError { message, hint }) => {
             ui.write_error(&format!("Error: {message}\n")).unwrap();
             if let Some(hint) = hint {
-                ui.write_hint(format!("Hint: {hint}\n")).unwrap();
+                writeln!(ui.hint(), "Hint: {hint}").unwrap();
             }
             1
         }

src/commands.rs

@@ -1222,11 +1222,12 @@ Set `ui.allow-init-native` to allow initializing a repo with the native backend.
     writeln!(ui, "Initialized repo in \"{}\"", relative_wc_path.display())?;
     if args.git && wc_path.join(".git").exists() {
         ui.write_warn("Empty repo created.\n")?;
-        ui.write_hint(format!(
+        writeln!(
+            ui.hint(),
             "Hint: To create a repo backed by the existing Git repo, run `jj init --git-repo={}` \
-             instead.\n",
+             instead.",
             relative_wc_path.display()
-        ))?;
+        )?;
     }
     Ok(())
 }

src/merge_tools.rs

@@ -485,10 +485,11 @@ fn editor_name_from_settings(
         Ok(editor_binary) => Ok(editor_binary),
         Err(_) => {
             let default_editor = "meld".to_string();
-            ui.write_hint(format!(
+            writeln!(
+                ui.hint(),
                 "Using default editor '{default_editor}'; you can change this by setting \
-                 ui.{diff_or_merge}-editor\n"
-            ))?;
+                 ui.{diff_or_merge}-editor"
+            )?;
             Ok(default_editor)
         }
     }

src/ui.rs

@@ -20,7 +20,7 @@ use std::{fmt, io, mem};
 use crossterm::tty::IsTty;
 
 use crate::config::FullCommandArgs;
-use crate::formatter::{Formatter, FormatterFactory};
+use crate::formatter::{Formatter, FormatterFactory, LabeledWriter};
 
 pub struct Ui {
     color: bool,
@@ -217,12 +217,8 @@ impl Ui {
         }
     }
 
-    pub fn write_hint(&mut self, text: impl AsRef<str>) -> io::Result<()> {
-        let mut formatter = self.stderr_formatter();
-        formatter.add_label("hint")?;
-        formatter.write_str(text.as_ref())?;
-        formatter.remove_label()?;
-        Ok(())
+    pub fn hint(&self) -> LabeledWriter<Box<dyn Formatter + '_>, &'static str> {
+        LabeledWriter::new(self.stderr_formatter(), "hint")
     }
 
     pub fn write_warn(&mut self, text: impl AsRef<str>) -> io::Result<()> {