LibWeb+LibGfx: Move UnicodeRange from LibWeb to LibGfx

In upcoming changes UnicodeRange is going to be used in LibGfx in
a class that represents font cascade list.

Userland/Libraries/LibGfx/Font/UnicodeRange.h

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2022-2023, Sam Atkins <atkinssj@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Assertions.h>
+#include <AK/String.h>
+
+namespace Gfx {
+
+class UnicodeRange {
+public:
+    UnicodeRange(u32 min_code_point, u32 max_code_point)
+        : m_min_code_point(min_code_point)
+        , m_max_code_point(max_code_point)
+    {
+        VERIFY(min_code_point <= max_code_point);
+    }
+
+    u32 min_code_point() const { return m_min_code_point; }
+    u32 max_code_point() const { return m_max_code_point; }
+
+    bool contains(u32 code_point) const
+    {
+        return m_min_code_point <= code_point && code_point <= m_max_code_point;
+    }
+
+    String to_string() const
+    {
+        if (m_min_code_point == m_max_code_point)
+            return MUST(String::formatted("U+{:x}", m_min_code_point));
+        return MUST(String::formatted("U+{:x}-{:x}", m_min_code_point, m_max_code_point));
+    }
+
+private:
+    u32 m_min_code_point;
+    u32 m_max_code_point;
+};
+
+}