Document fix for literal_compare == False (#3207)

Co-authored-by: Sorin Sbarnea <[email protected]>

src/ansiblelint/rules/literal_compare.md

@@ -4,6 +4,9 @@ This rule checks for literal comparison with the `when` clause.
 Literal comparison, like `when: var == True`, is unnecessarily complex.
 Use `when: var` to keep your playbooks simple.
 
+Similarly, a check like `when: var != True` or `when: var == False`
+should be replaced with `when: not var`.
+
 ## Problematic Code
 
 ```yaml