Added todo notes to "boolean logic" doc

Signed-off-by: Serhii Horodilov <sgorodil@gmail.com>

Author: shorodilov

src/basics/bool_logic.txt

@@ -243,3 +243,7 @@ priority (which is higher than that of the Boolean operations).
     +------------+-----------------------------------+
     | ``is not`` | negated object identity           |
     +------------+-----------------------------------+
+
+.. todo: add examples and description(s)
+
+.. todo: chaining with boolean operators