Doc: Json classes added to list of implic.shared classes

Task-number: QTBUG-44053
Change-Id: I52a1b6c413aaa594bfee9bf7484c3d0ce7e9c9fa
Reviewed-by: Topi Reiniö <topi.reinio@digia.com>

src/corelib/json/qjsonarray.cpp

@@ -47,6 +47,7 @@ QT_BEGIN_NAMESPACE
     \class QJsonArray
     \inmodule QtCore
     \ingroup json
+    \ingroup shared
     \reentrant
     \since 5.0
 

src/corelib/json/qjsondocument.cpp

@@ -47,6 +47,7 @@ QT_BEGIN_NAMESPACE
 /*! \class QJsonDocument
     \inmodule QtCore
     \ingroup json
+    \ingroup shared
     \reentrant
     \since 5.0
 

src/corelib/json/qjsonobject.cpp

@@ -46,6 +46,7 @@ QT_BEGIN_NAMESPACE
     \class QJsonObject
     \inmodule QtCore
     \ingroup json
+    \ingroup shared
     \reentrant
     \since 5.0
 

src/corelib/json/qjsonparser.cpp

@@ -77,6 +77,7 @@ QT_BEGIN_NAMESPACE
     \class QJsonParseError
     \inmodule QtCore
     \ingroup json
+    \ingroup shared
     \reentrant
     \since 5.0
 

src/corelib/json/qjsonvalue.cpp

@@ -46,6 +46,7 @@ QT_BEGIN_NAMESPACE
     \class QJsonValue
     \inmodule QtCore
     \ingroup json
+    \ingroup shared
     \reentrant
     \since 5.0