style: use fat arrow for single-line methods

lib/src/commit.dart

@@ -100,7 +100,5 @@ class Commit {
   Oid get tree => Oid(bindings.tree(_commitPointer));
 
   /// Releases memory allocated for commit object.
-  void free() {
+  void free() => bindings.free(_commitPointer);
-    bindings.free(_commitPointer);
-  }
 }

lib/src/config.dart

@@ -140,7 +140,5 @@ class Config {
   }
 
   /// Releases memory allocated for config object.
-  void free() {
+  void free() => bindings.free(_configPointer);
-    bindings.free(_configPointer);
-  }
 }

lib/src/index.dart

@@ -138,9 +138,7 @@ class Index {
   void removeAll(List<String> path) => bindings.removeAll(_indexPointer, path);
 
   /// Releases memory allocated for index object.
-  void free() {
+  void free() => bindings.free(_indexPointer);
-    bindings.free(_indexPointer);
-  }
 }
 
 class IndexEntry {

lib/src/odb.dart

@@ -26,7 +26,5 @@ class Odb {
   }
 
   /// Releases memory allocated for odb object.
-  void free() {
+  void free() => bindings.free(_odbPointer);
-    bindings.free(_odbPointer);
-  }
 }

lib/src/reference.dart

@@ -238,7 +238,5 @@ class Reference {
   int get hashCode => _refPointer.address.hashCode;
 
   /// Releases memory allocated for reference object.
-  void free() {
+  void free() => bindings.free(_refPointer);
-    bindings.free(_refPointer);
-  }
 }

lib/src/reflog.dart

@@ -43,9 +43,7 @@ class RefLog {
   }
 
   /// Releases memory allocated for reflog object.
-  void free() {
+  void free() => bindings.free(_reflogPointer);
-    bindings.free(_reflogPointer);
-  }
 }
 
 class RefLogEntry {

lib/src/repository.dart

@@ -212,9 +212,7 @@ class Repository {
   }
 
   /// Releases memory allocated for repository object.
-  void free() {
+  void free() => bindings.free(_repoPointer);
-    bindings.free(_repoPointer);
-  }
 
   /// Returns the configuration file for this repository.
   ///

lib/src/revwalk.dart

@@ -81,7 +81,5 @@ class RevWalk {
   void simplifyFirstParent() => bindings.simplifyFirstParent(_revWalkPointer);
 
   /// Releases memory allocated for [RevWalk] object.
-  void free() {
+  void free() => bindings.free(_revWalkPointer);
-    bindings.free(_revWalkPointer);
-  }
 }

lib/src/signature.dart

@@ -66,7 +66,5 @@ class Signature {
   int get hashCode => _signaturePointer.address.hashCode;
 
   /// Releases memory allocated for signature object.
-  void free() {
+  void free() => bindings.free(_signaturePointer);
-    bindings.free(_signaturePointer);
-  }
 }