Math: Refactor

Signed-off-by: Ce Gao <ce.gao@outlook.com>

Author: gaocegege

src/generate.py

@@ -175,8 +175,6 @@ def render_reference_index(self):
             ('Typography', 'Attributes'),
             ('Typography', 'Metrics'),
             ('Math', ''),
-            ('Math', 'Operators'),
-            ('Math', 'Bitwise Operators'),
             ('Math', 'Calculation'),
             ('Math', 'Trigonometry'),
             ('Math', 'Random'),