Add opt out from math in query string

app.py

@@ -237,8 +237,8 @@ class PageRevision(BaseModel):
     @property
     def text(self):
         return self.textref.get_content()
-    def html(self):
-        return md(self.text, math=self.page.is_math_enabled)
+    def html(self, *, math=True):
+        return md(self.text, math=self.page.is_math_enabled and math)
     def human_pub_date(self):
         delta = datetime.datetime.now() - self.pub_date
         T = partial(get_string, g.lang)

templates/view.html

@@ -16,7 +16,7 @@
   {% block history_nav %}{% endblock %}
 
   <div class="inner-content">
-    {{ rev.html()|safe }}
+    {{ rev.html(math = request.args.get('math') not in ['0', 'false', 'no', 'off'])|safe }}
   </div>
 
   {% if p.tags %}