Common: Add GSVector

Mostly based on PCSX2.

src/common/gsvector_formatter.h

@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: 2024 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-License-Identifier: (GPL-3.0 OR CC-BY-NC-ND-4.0)
+
+#pragma once
+
+#include "gsvector.h"
+#include "small_string.h"
+
+#include "fmt/format.h"
+
+template<>
+struct fmt::formatter<GSVector4i> : formatter<std::string_view>
+{
+  auto format(const GSVector4i& rc, format_context& ctx) const
+  {
+    const TinyString str =
+      TinyString::from_format("{},{} => {},{} ({}x{})", rc.left, rc.top, rc.right, rc.bottom, rc.width(), rc.height());
+
+    return fmt::formatter<std::string_view>::format(str.view(), ctx);
+  }
+};