Use QRegularExpression instead of deprecated QRegExp

Now it follows closely the definition of wildcard for glob patterns.
The backslash (\) character is not an escape char in this context.
In order to match one of the special characters, place it in square
brackets (for example, [?]).

src/base/utils/string.cpp

@@ -33,10 +33,15 @@
 
 #include <QCollator>
 #include <QLocale>
-#include <QRegExp>
 #include <QtGlobal>
 #include <QVector>
 
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+#include <QRegularExpression>
+#else
+#include <QRegExp>
+#endif
+
 #if defined(Q_OS_MACOS) || defined(__MINGW32__)
 #define QBT_USES_QTHREADSTORAGE
 #include <QThreadStorage>
@@ -181,14 +186,21 @@ QString Utils::String::fromDouble(const double n, const int precision)
     return QLocale::system().toString(std::floor(n * prec) / prec, 'f', precision);
 }
 
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+QString Utils::String::wildcardToRegexPattern(const QString &pattern)
+{
+    return QRegularExpression::wildcardToRegularExpression(pattern, QRegularExpression::UnanchoredWildcardConversion);
+}
+#else
 // This is marked as internal in QRegExp.cpp, but is exported. The alternative would be to
 // copy the code from QRegExp::wc2rx().
 QString qt_regexp_toCanonical(const QString &pattern, QRegExp::PatternSyntax patternSyntax);
 
-QString Utils::String::wildcardToRegex(const QString &pattern)
+QString Utils::String::wildcardToRegexPattern(const QString &pattern)
 {
     return qt_regexp_toCanonical(pattern, QRegExp::Wildcard);
 }
+#endif
 
 std::optional<bool> Utils::String::parseBool(const QString &string)
 {

src/base/utils/string.h

@@ -50,7 +50,7 @@ namespace Utils::String
         return (naturalCompare(left, right, caseSensitivity) < 0);
     }
 
-    QString wildcardToRegex(const QString &pattern);
+    QString wildcardToRegexPattern(const QString &pattern);
 
     template <typename T>
     T unquote(const T &str, const QString &quotes = QChar('"'))