remove deprecated constructions

src/Entity/Browser/Container/Page/Content/Gemtext.php

@@ -15,8 +15,6 @@ class Gemtext extends \Yggverse\Yoda\Abstract\Entity\Browser\Container\Page\Cont
         bool $preformatted = false
     ): void
     {
-        $this->_source = $value;
-
         $document = new Document(
             $value
         );

src/Entity/Browser/Container/Page/Content/Plain.php

@@ -10,8 +10,6 @@ class Plain extends \Yggverse\Yoda\Abstract\Entity\Browser\Container\Page\Conten
         string $value
     ): void
     {
-        $this->_source = $value;
-
         $this->gtk->set_markup(
             sprintf(
                 '<tt>%s</tt>',