Do no add an empty line before every header.

Author: SpacePossum

src/Differ.php

@@ -135,7 +135,7 @@ private function getBuffer(array $diff, array $old, $start, $end)
         for ($i = $start; $i < $end; $i++) {
             if (isset($old[$i])) {
                 $i      = $old[$i];
-                $buffer = $this->getDiffBufferElementNew($diff, "\n" . $buffer, $i);
+                $buffer = $this->getDiffBufferElementNew($diff, $buffer, $i);
             } else {
                 $buffer = $this->getDiffBufferElement($diff, $buffer, $i);
             }

tests/DifferTest.php

@@ -306,6 +306,44 @@ public function textProvider()
                 "A\nB",
                 "A1\nB",
             ),
+            array(
+                <<<EOF
+--- Original
++++ New
+@@ @@
+ a
+-b
++p
+@@ @@
+ i
+-j
++w
+ k
+
+EOF
+            ,
+                "a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk",
+                "a\np\nc\nd\ne\nf\ng\nh\ni\nw\nk",
+            ),
+            array(
+                <<<EOF
+--- Original
++++ New
+@@ @@
+ a
+-b
++p
+@@ @@
+ i
+-j
++w
+ k
+
+EOF
+                ,
+                "a\nb\nc\nd\ne\nf\ng\nh\ni\nj\nk",
+                "a\np\nc\nd\ne\nf\ng\nh\ni\nw\nk",
+            ),
         );
     }