[common] merge RenderBackend and ShaderBackend options (#3313)

first of all it makes UI a tad bit more simple and benefits the end user
second, it allows to add new backends a bit more easily
and also, there was a shader backend option in android... we don't use opengl in android
so may as well save ourselves the trouble, aye

![image](/attachments/c0195bca-da18-4907-9e4a-3b62c4292f1a)

Signed-off-by: lizzie <lizzie@eden-emu.dev>

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/3313
Reviewed-by: Maufeat <sahyno1996@gmail.com>
Reviewed-by: DraVee <dravee@eden-emu.dev>
Co-authored-by: lizzie <lizzie@eden-emu.dev>
Co-committed-by: lizzie <lizzie@eden-emu.dev>

src/video_core/video_core.cpp

@@ -1,3 +1,6 @@
+// SPDX-FileCopyrightText: Copyright 2025 Eden Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
 // SPDX-FileCopyrightText: 2014 Citra Emulator Project
 // SPDX-License-Identifier: GPL-2.0-or-later
 
@@ -22,12 +25,12 @@ std::unique_ptr<VideoCore::RendererBase> CreateRenderer(
     auto& device_memory = system.Host1x().MemoryManager();
 
     switch (Settings::values.renderer_backend.GetValue()) {
-    case Settings::RendererBackend::OpenGL:
-        return std::make_unique<OpenGL::RendererOpenGL>(emu_window, device_memory, gpu,
-                                                        std::move(context));
+    case Settings::RendererBackend::OpenGL_GLSL:
+    case Settings::RendererBackend::OpenGL_GLASM:
+    case Settings::RendererBackend::OpenGL_SPIRV:
+        return std::make_unique<OpenGL::RendererOpenGL>(emu_window, device_memory, gpu, std::move(context));
     case Settings::RendererBackend::Vulkan:
-        return std::make_unique<Vulkan::RendererVulkan>(emu_window, device_memory, gpu,
-                                                        std::move(context));
+        return std::make_unique<Vulkan::RendererVulkan>(emu_window, device_memory, gpu, std::move(context));
     case Settings::RendererBackend::Null:
         return std::make_unique<Null::RendererNull>(emu_window, gpu, std::move(context));
     default: