video_core: Use contains when possible

src/video_core/renderer_opengl/gl_arb_decompiler.cpp

@@ -1463,9 +1463,8 @@ void ARBDecompiler::Exit() {
     }
 
     const auto safe_get_register = [this](u32 reg) -> std::string {
-        // TODO(Rodrigo): Replace with contains once C++20 releases
         const auto& used_registers = ir.GetRegisters();
-        if (used_registers.find(reg) != used_registers.end()) {
+        if (used_registers.contains(reg)) {
             return fmt::format("R{}.x", reg);
         }
         return "{0, 0, 0, 0}.x";

src/video_core/renderer_opengl/gl_shader_decompiler.cpp

@@ -2265,8 +2265,7 @@ private:
         }
         const auto& used_registers = ir.GetRegisters();
         const auto SafeGetRegister = [&](u32 reg) -> Expression {
-            // TODO(Rodrigo): Replace with contains once C++20 releases
-            if (used_registers.find(reg) != used_registers.end()) {
+            if (used_registers.contains(reg)) {
                 return {GetRegister(reg), Type::Float};
             }
             return {"0.0f", Type::Float};