New syntax highlighter not complete.

- Supports comments
- more efficient as it scans the text block instead of repeatedly searching throught the whole block
- type matching based on catalog (but need to add aliases manually)
- added many keywords

todo:
- heap corruption bug
- symbol stops at special char like parenthese or operator or something similar.

SqlSyntaxHighlighter.h

@@ -0,0 +1,34 @@
+#ifndef SQLSYNTAXHIGHLIGHTER_H
+#define SQLSYNTAXHIGHLIGHTER_H
+
+#include <QSyntaxHighlighter>
+#include <QTextFormat>
+#include <unordered_set>
+#include "util.h"
+
+using t_SymbolSet = std::unordered_set<QString>;
+
+class PgTypeContainer;
+
+class SqlSyntaxHighlighter : public QSyntaxHighlighter
+{
+	Q_OBJECT
+
+public:
+	SqlSyntaxHighlighter(QTextDocument *parent = nullptr);
+	~SqlSyntaxHighlighter();
+
+	void setTypes(const PgTypeContainer *types);
+protected:
+	void highlightBlock(const QString &text) override;
+
+private:
+	QTextCharFormat m_keywordFormat;
+	QTextCharFormat m_commentFormat;
+	QTextCharFormat m_quotedStringFormat;
+	QTextCharFormat m_typeFormat;
+
+	t_SymbolSet m_typeNames;
+};
+
+#endif // SQLSYNTAXHIGHLIGHTER_H