Fix twig error lineno off by 2

lib/Twig/Compiler.php

@@ -217,7 +217,7 @@ class Twig_Compiler implements Twig_CompilerInterface
                 $this->sourceLine += substr_count($this->source, "\n", $this->sourceOffset);
             }
             $this->sourceOffset = strlen($this->source);
-            $this->debugInfo[$this->sourceLine] = $node->getLine();
+            $this->debugInfo[$this->sourceLine + 2] = $node->getLine();
 
             $this->lastLine = $node->getLine();
             $this->write("// line {$node->getLine()}\n");

test/Twig/Tests/Node/ModuleTest.php

@@ -90,7 +90,7 @@ class __TwigTemplate_be925a7b06dda0dfdbd18a1509f7eb34 extends Twig_Template
 
     public function getDebugInfo()
     {
-        return array (  17 => 1,);
+        return array (  19 => 1,);
     }
 }
 EOF
@@ -142,7 +142,7 @@ class __TwigTemplate_be925a7b06dda0dfdbd18a1509f7eb34 extends Twig_Template
 
     public function getDebugInfo()
     {
-        return array (  22 => 1,);
+        return array (  24 => 1,);
     }
 }
 EOF

test/Twig/Tests/Node/SandboxedModuleTest.php

@@ -98,7 +98,7 @@ class __TwigTemplate_be925a7b06dda0dfdbd18a1509f7eb34 extends Twig_Template
 
     public function getDebugInfo()
     {
-        return array (  18 => 1,);
+        return array (  20 => 1,);
     }
 }
 EOF