start to add ability to merge tunes

started refactoring tune builders to use string type hint instead of StringAtom

src/Domain/Modules/Interpreter/Lexicon/Tempo.php

@@ -3,6 +3,7 @@ namespace XaiCorp\AbcParser\Domain\Modules\Interpreter\Lexicon;
 
 use Enzyme\Axiom\Atoms\StringAtom;
 use XaiCorp\AbcParser\Domain\Atoms\UnsignedIntegerAtom;
+use XaiCorp\AbcParser\Domain\Core\TuneBuilder;
 use XaiCorp\AbcParser\Domain\Modules\Interpreter\Builder;
 use XaiCorp\AbcParser\Domain\Modules\Interpreter\Context;
 
@@ -11,11 +12,11 @@ class Tempo implements Lex
     use LineKeyDataTrait;
 
     /**
-     * @var Builder
+     * @var TuneBuilder
      */
     protected $builder;
 
-    public function __construct(Builder $builder)
+    public function __construct(TuneBuilder $builder)
     {
         $this->builder = $builder;
     }