IDE开发系列（2）扩展的IDE框架设计

扩展之前的IDE框架，包含语法高亮、代码补全、项目管理等所有建议功能。

1. 语法高亮实现

// SyntaxHighlighter.h
#pragma once

#include <QSyntaxHighlighter>
#include <QTextCharFormat>
#include <QRegularExpression>

class SyntaxHighlighter : public QSyntaxHighlighter
{
    Q_OBJECT

public:
    SyntaxHighlighter(QTextDocument *parent = nullptr);

protected:
    void highlightBlock(const QString &text) override;

private:
    struct HighlightingRule
    {
        QRegularExpression pattern;
        QTextCharFormat format;
    };
    QVector<HighlightingRule> highlightingRules;

    QRegularExpression commentStartExpression;
    QRegularExpression commentEndExpression;

    QTextCharFormat keywordFormat;
    QTextCharFormat classFormat;
    QTextCharFormat si