AK: Allow constructing a JsonValue from a StringView explicitly

The next commit will destroy overload detection otherwise, so let's add
this constructor. Currently, the same work is already done implicitly
through the implicit `String(StringView)` constructor.

AK/JsonValue.cpp

@@ -7,6 +7,7 @@
 #include <AK/JsonArray.h>
 #include <AK/JsonObject.h>
 #include <AK/JsonValue.h>
+#include <AK/StringView.h>
 
 #ifndef KERNEL
 #    include <AK/JsonParser.h>
@@ -184,6 +185,11 @@ JsonValue::JsonValue(const String& value)
     }
 }
 
+JsonValue::JsonValue(StringView value)
+    : JsonValue(value.to_string())
+{
+}
+
 JsonValue::JsonValue(const JsonObject& value)
     : m_type(Type::Object)
 {

AK/JsonValue.h

@@ -54,6 +54,7 @@ public:
     JsonValue(bool);
     JsonValue(const char*);
     JsonValue(const String&);
+    JsonValue(StringView);
     JsonValue(const JsonArray&);
     JsonValue(const JsonObject&);