QT_NO_AS_CONST: rename and add docs

Give it a name in line with the function name:
qAsConst -> QT_NO_QASCONST, as already done for qExchange.
We can do this because we never documented the macro itself.
So, while at it: also document the macro.

Change-Id: I6eb0834df438e4f4e818ef2cf8e702ed156dc253
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

cmake/QtInternalTargets.cmake

@@ -156,7 +156,7 @@ qt_internal_add_target_aliases(PlatformToolInternal)
 target_link_libraries(PlatformToolInternal INTERFACE PlatformAppInternal)
 
 qt_internal_add_global_definition(QT_NO_JAVA_STYLE_ITERATORS)
-qt_internal_add_global_definition(QT_NO_AS_CONST)
+qt_internal_add_global_definition(QT_NO_QASCONST)
 qt_internal_add_global_definition(QT_NO_QEXCHANGE)
 qt_internal_add_global_definition(QT_NO_NARROWING_CONVERSIONS_IN_CONNECT)
 qt_internal_add_global_definition(QT_EXPLICIT_QFILE_CONSTRUCTION_FROM_PATH)

src/corelib/global/qttypetraits.h

@@ -24,7 +24,7 @@ constexpr std::underlying_type_t<Enum> qToUnderlying(Enum e) noexcept
     return static_cast<std::underlying_type_t<Enum>>(e);
 }
 
-#ifndef QT_NO_AS_CONST
+#ifndef QT_NO_QASCONST
 #if QT_DEPRECATED_SINCE(6, 6)
 
 // this adds const to non-const objects (like std::as_const)
@@ -36,7 +36,7 @@ template <typename T>
 void qAsConst(const T &&) = delete;
 
 #endif // QT_DEPRECATED_SINCE(6, 6)
-#endif // QT_NO_AS_CONST
+#endif // QT_NO_QASCONST
 
 #ifndef QT_NO_QEXCHANGE
 

src/corelib/global/qttypetraits.qdoc

@@ -54,6 +54,20 @@
 
     To prevent this construct from compiling (and failing at runtime), qAsConst() has
     a second, deleted, overload which binds to rvalues.
+
+    \note You can make the qAsConst() function unavailable by defining
+    the \l{QT_NO_QASCONST} macro.
+*/
+
+/*!
+    \macro QT_NO_QASCONST
+    \since 6.8
+    \relates <QtTypeTraits>
+
+    Defining this macro removes the availability of the qAsConst()
+    function.
+
+    \sa qAsConst
 */
 
 /*!