Fixed path to all OnStage 2025 photo

Author: ChristianH99

docs/source/competitions/rcj-2025/index.rst

@@ -1,7 +1,7 @@
 RoboCup 2025 - Salvador (Brazil)
 ==========================================
 
-.. image:: /onstage/_static/competitions/rcj-2025/2025_onstage.JPEG
+.. image:: /_static/competitions/rcj-2025/2025_onstage.JPEG
    :alt: RoboCup 2025 All OnStage Photo
    :align: center
    :class: only-light