Update loop docs to also describe register:'s value when inside loop. (#20991)

docs/docsite/rst/playbooks_loops.rst

@@ -463,7 +463,7 @@ That's how!
 Using register with a loop
 ``````````````````````````
 
-When using ``register`` with a loop, the data structure placed in the variable will contain a ``results`` attribute that is a list of all responses from the module.
+After using ``register`` with a loop, the data structure placed in the variable will contain a ``results`` attribute that is a list of all responses from the module.
 
 Here is an example of using ``register`` with ``with_items``::
 
@@ -520,6 +520,15 @@ Subsequent loops over the registered variable to inspect the results may look li
       when: item.rc != 0
       with_items: "{{ echo.results }}"
 
+During iteration, the result of the current item will be placed in the variable:
+
+    - shell: echo "{{ item }}"
+      with_items:
+        - one
+        - two
+      register: echo
+      changed_when: echo.stdout != "one"
+
 
 
 .. _looping_over_the_inventory: