[docs] Fix \since for qHash(qfloat16)

The patch adding the function unexpectedly made it into 6.5 before
6.5.3 was forked off. That's nice, as it reduces the number of
releases with a broken implementation, but the documentation and
ChangeLog were written assuming a merge for 6.5.4.

Fix the documentation.

Amends 6da6a17de9ccfcd5458ea72507b131660e0ab948.

[ChangeLog][Editorial][QtCore] Delete the old entry for
qHash(qfloat16), keep the one from this commit.

[ChangeLog][QtCore] Fixed qHash(qfloat16) which was broken from 6.5.0
to 6.5.2, inclusive. If you compiled against one of the affected Qt
versions, you need to recompile against either Qt 6.4 or earlier or
6.5.3 or later, because the problematic code is inline.

Task-number: QTBUG-116064
Task-number: QTBUG-116076
Change-Id: If8fa35fb8532cf0bbf2ba0438694d95fd9bd6991
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 0f19cafc3cbb85dfd67c5c6f7421943e9c063ea1)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
(cherry picked from commit 8e14e13c16249f5dd4f25e8d681498e393241493)
(cherry picked from commit 3974778dc9bcb427e9dcdc20b179c7c3aedf737b)

src/corelib/global/qfloat16.cpp

@@ -365,15 +365,15 @@ Q_CORE_EXPORT void qFloatFromFloat16(float *out, const qfloat16 *in, qsizetype l
 
 /*!
     \fn size_t qfloat16::qHash(qfloat16 key, size_t seed)
-    \since 6.5.4
+    \since 6.5.3
     \relates qfloat16
 
     Returns the hash value for the \a key, using \a seed to seed the
     calculation.
 
     \note In Qt versions before 6.5, this operation was provided by the
-    qHash(float) overload. In Qt versions 6.5.0 to 6.5.3, this functionality
-    was broken in various ways. In Qt versions 6.5.4 and 6.6 onwards, this
+    qHash(float) overload. In Qt versions 6.5.0 to 6.5.2, this functionality
+    was broken in various ways. In Qt versions 6.5.3 and 6.6 onwards, this
     overload restores the Qt 6.4 behavior.
 */