AK: Add JsonValue(const char*).

This should obviously become a string, but if we don't have it, constructing
from a string literal ends up creating a boolean value.

AK/JsonValue.cpp

@@ -76,6 +76,11 @@ JsonValue::JsonValue(unsigned value)
     }
 }
 
+JsonValue::JsonValue(const char* cstring)
+    : JsonValue(String(cstring))
+{
+}
+
 JsonValue::JsonValue(double value)
     : m_type(Type::Double)
 {

AK/JsonValue.h

@@ -34,6 +34,7 @@ public:
     JsonValue(unsigned);
     JsonValue(double);
     JsonValue(bool);
+    JsonValue(const char*);
     JsonValue(const String&);
     JsonValue(const JsonArray&);
     JsonValue(const JsonObject&);