Added comparison-with-itself message example (#6157)

Co-authored-by: Vladyslav Krylasov <[email protected]>
Co-authored-by: Pierre Sassoulas <[email protected]>

Author: 3 people

doc/data/messages/c/comparison-with-itself/bad.py

@@ -0,0 +1,3 @@
+def is_an_orange(fruit):
+    an_orange = "orange"
+    return fruit == fruit  # [comparison-with-itself]

doc/data/messages/c/comparison-with-itself/good.py

@@ -0,0 +1,3 @@
+def is_an_orange(fruit):
+    an_orange = "orange"
+    return an_orange == fruit