feat: exit code is 0 when performing fix (#52)

Fixes #51

Example: 

![image](https://github.com/Boshen/cargo-shear/assets/6513197/96525ba6-1689-43b6-bf07-03c1e52b511c)

src/lib.rs

@@ -42,14 +42,16 @@ pub struct CargoShear {
     options: CargoShearOptions,
 
     unused_dependencies: usize,
+
+    fixed_dependencies: usize,
 }
 
 type Deps = HashSet<String>;
 
 impl CargoShear {
     #[must_use]
     pub const fn new(options: CargoShearOptions) -> Self {
-        Self { options, unused_dependencies: 0 }
+        Self { options, unused_dependencies: 0, fixed_dependencies: 0 }
     }
 
     #[must_use]
@@ -59,7 +61,13 @@ impl CargoShear {
 
         match self.shear() {
             Ok(()) => {
-                let has_deps = self.unused_dependencies > 0;
+                let has_fixed = self.fixed_dependencies > 0;
+
+                if has_fixed {
+                    println!("Fixed {} dependencies!", self.fixed_dependencies);
+                }
+
+                let has_deps = (self.unused_dependencies - self.fixed_dependencies) > 0;
 
                 if has_deps {
                     println!(
@@ -292,7 +300,11 @@ impl CargoShear {
         Ok(imports)
     }
 
-    fn try_fix_package(&self, cargo_toml_path: &Path, unused_dep_names: &[String]) -> Result<()> {
+    fn try_fix_package(
+        &mut self,
+        cargo_toml_path: &Path,
+        unused_dep_names: &[String],
+    ) -> Result<()> {
         if !self.options.fix {
             return Ok(());
         }
@@ -323,6 +335,7 @@ impl CargoShear {
             }
         }
 
+        self.fixed_dependencies += unused_dep_names.len();
         let serialized = manifest.to_string();
         fs::write(cargo_toml_path, serialized)?;
         Ok(())