Make sure font weight value is within allowed range

src/TerminalDisplay.cpp

@@ -777,10 +777,12 @@ void TerminalDisplay::drawCharacters(QPainter& painter,
         return;
     }
 
+    static constexpr int MaxFontWeight = 99; // https://doc.qt.io/qt-5/qfont.html#Weight-enum
+
     const int normalWeight = font().weight();
     // +26 makes "bold" from "normal", "normal" from "light", etc. It is 26 instead of not 25 to prefer
     // bolder weight when 25 falls in the middle between two weights. See QFont::Weight
-    const int boldWeight = normalWeight + 26;
+    const int boldWeight = qMin(normalWeight + 26, MaxFontWeight);
 
     const auto isBold = [boldWeight](const QFont &font) { return font.weight() >= boldWeight; };