Docs: fix QT_NO_FOREACH/KEYWORDS macro documentation

QT_NO_FOREACH didn't related to anything so the documentation
wasn't generated, and QT_NO_KEYWORDS wasn't documented but
referenced.

Pick-to: 6.7
Change-Id: I7b79e61519c186d10f8e8c674705adb3d10bd53a
Reviewed-by: Venugopal Shivashankar <Venugopal.Shivashankar@qt.io>

src/corelib/doc/src/foreach-keyword.qdoc

@@ -81,7 +81,10 @@
 /*!
     \macro QT_NO_FOREACH
     \since 6.0
+    \relates <QtGlobal>
 
     Defining this macro removes the availability of Qt's \c foreach
     loop.
+
+    \sa QT_NO_KEYWORDS
 */

src/corelib/global/qglobal.cpp

@@ -169,6 +169,19 @@ bool QInternal::activateCallbacks(Callback cb, void **parameters)
     return false;
 }
 
+/*!
+    \macro QT_NO_KEYWORDS
+    \relates <QtGlobal>
+
+    Define this macro to disable the Qt-specific keywords that are usually enabled,
+    such as \c signals and \c slots. Use \c Q_SIGNALS and \c Q_SLOTS instead.
+
+    Libraries should define this macro to make sure that they don't use the generic
+    keywords without the \c Q_ prefix in their public headers.
+
+    \sa QT_NO_FOREACH
+*/
+
 /*!
     \macro QT_NAMESPACE
     \internal