collect the mtime *after* formatting.

Fixes #118

README.md

@@ -38,6 +38,7 @@ quite tricky.
 ## Usage
 
 `$ treefmt --help`
+
 ```
 treefmt 0.2.3
 ✨  format all your language!

src/engine.rs

@@ -189,6 +189,9 @@ pub fn run_treefmt(
             } else {
                 let start_time = Instant::now();
 
+                // Run the formatter
+                formatter.clone().fmt(&paths)?;
+
                 // Get the new mtimes and compare them to the original ones
                 let new_paths = paths
                     .clone()
@@ -200,8 +203,6 @@ pub fn run_treefmt(
                         sum
                     });
 
-                formatter.clone().fmt(&paths)?;
-
                 info!(
                     "{}: {} files processed in {:.2?}",
                     formatter.name,