AK: Add NumericLimits specialization for char.

This is yet another bug because of the 'char'/'signed char'/'unsigned char' shit.

AK/NumericLimits.h

@@ -48,6 +48,13 @@ struct NumericLimits<signed char> {
     static constexpr bool is_signed() { return true; }
 };
 
+template<>
+struct NumericLimits<char> {
+    static constexpr char min() { return -__SCHAR_MAX__ - 1; }
+    static constexpr char max() { return __SCHAR_MAX__; }
+    static constexpr bool is_signed() { return true; }
+};
+
 template<>
 struct NumericLimits<short> {
     static constexpr short min() { return -__SHRT_MAX__ - 1; }