docs: from_parent - add minimal before/after example

fixup: fix from_parent version

Author: RonnyPfannschmidt

doc/en/deprecations.rst

@@ -37,11 +37,15 @@ display captured output when tests fail: ``no``, ``stdout``, ``stderr``, ``log``
 Node Construction changed to ``Node.from_parent``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
-.. deprecated:: 5.3
+.. deprecated:: 5.4
 
 The construction of nodes new should use the named constructor ``from_parent``.
 This limitation in api surface intends to enable better/simpler refactoring of the collection tree.
 
+This means that instead of :code:``MyItem(name="foo", parent=collector, obj=42)``
+one now has to invoke :code:``MyItem.from_parent(collector, name="foo")``.
+
+
 
 ``junit_family`` default value change to "xunit2"
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~