LibSyntax+Userland: Make LibSyntax not depend on LibGUI

This moves some stuff around to make LibGUI depend on LibSyntax instead
of the other way around, as not every application that wishes to do
syntax highlighting is necessarily a LibGUI (or even a GUI) application.

Userland/Libraries/LibSyntax/TextPosition.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2023, Ali Mohammad Pur <mpfard@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Format.h>
+
+namespace Syntax {
+
+class TextPosition {
+public:
+    TextPosition() = default;
+    TextPosition(size_t line, size_t column)
+        : m_line(line)
+        , m_column(column)
+    {
+    }
+
+    bool is_valid() const { return m_line != 0xffffffffu && m_column != 0xffffffffu; }
+
+    size_t line() const { return m_line; }
+    size_t column() const { return m_column; }
+
+    void set_line(size_t line) { m_line = line; }
+    void set_column(size_t column) { m_column = column; }
+
+    bool operator==(TextPosition const& other) const { return m_line == other.m_line && m_column == other.m_column; }
+    bool operator!=(TextPosition const& other) const { return m_line != other.m_line || m_column != other.m_column; }
+    bool operator<(TextPosition const& other) const { return m_line < other.m_line || (m_line == other.m_line && m_column < other.m_column); }
+    bool operator>(TextPosition const& other) const { return *this != other && !(*this < other); }
+    bool operator>=(TextPosition const& other) const { return *this > other || (*this == other); }
+
+private:
+    size_t m_line { 0xffffffff };
+    size_t m_column { 0xffffffff };
+};
+
+}
+
+template<>
+struct AK::Formatter<Syntax::TextPosition> : AK::Formatter<FormatString> {
+    ErrorOr<void> format(FormatBuilder& builder, Syntax::TextPosition const& value)
+    {
+        if (value.is_valid())
+            return Formatter<FormatString>::format(builder, "({},{})"sv, value.line(), value.column());
+
+        return builder.put_string("TextPosition(Invalid)"sv);
+    }
+};