Match exact words to trigger calculator widget

The calculator was previously triggered for partial matches with words
like "calc", which meant searches containing the word "calcium" would
cause the calculator widget to appear.

app/utils/search.py

@@ -109,7 +109,9 @@ class Search:
         self.widget = "ip" if re.search("([^a-z0-9]|^)my *[^a-z0-9] *(ip|internet protocol)" +
                         "($|( *[^a-z0-9] *(((addres|address|adres|" +
                         "adress)|a)? *$)))", self.query.lower()) else self.widget
-        self.widget = 'calculator' if re.search("calculator|calc|calclator|math", self.query.lower()) else self.widget
+        self.widget = 'calculator' if re.search(
+                r"\bcalculator\b|\bcalc\b|\bcalclator\b|\bmath\b",
+                self.query.lower()) else self.widget
         return self.query
 
     def generate_response(self) -> str: