Print empty commit info without trailing hyphen

Author: dtolnay

src/bin/main.rs

@@ -450,13 +450,14 @@ are included as out of line modules from `src/lib.rs`."
 }
 
 fn print_version() {
-    let version_info = format!(
-        "{}-{}",
-        option_env!("CARGO_PKG_VERSION").unwrap_or("unknown"),
-        include_str!(concat!(env!("OUT_DIR"), "/commit-info.txt"))
-    );
+    let version_number = option_env!("CARGO_PKG_VERSION").unwrap_or("unknown");
+    let commit_info = include_str!(concat!(env!("OUT_DIR"), "/commit-info.txt"));
 
-    println!("rustfmt {version_info}");
+    if commit_info.is_empty() {
+        println!("rustfmt {version_number}");
+    } else {
+        println!("rustfmt {version_number}-{commit_info}");
+    }
 }
 
 fn determine_operation(matches: &Matches) -> Result<Operation, OperationError> {