Added no-else-break message example (#6262)

Co-authored-by: Pierre Sassoulas <pierre.sassoulas@gmail.com>

Author: matusvalo

doc/data/messages/n/no-else-break/bad.py

@@ -0,0 +1,6 @@
+def next_seven_elements(iterator):
+    for i, item in enumerate(iterator):
+        if i == 7:  # [no-else-break]
+            break
+        else:
+            yield item

doc/data/messages/n/no-else-break/good.py

@@ -0,0 +1,5 @@
+def next_seven_elements(iterator):
+    for i, item in enumerate(iterator):
+        if i == 7:
+            break
+        yield item