temperature: number hints, to link them to the tasks

Author: ErikSchierboom

exercises/concept/temperature/.docs/hints.md

@@ -1,12 +1,12 @@
 # Hints
 
-## Convert Fahrenheit to Celsius
+## 1. Convert Fahrenheit to Celsius
 
 - Temperature in degrees Celsius is defined as: T(°C) = (T(°F) - 32) / 1.8
 - The temperature in Fahrenheit is provided as an `Integer` and must return Celsius as a `Float`.
   The `fromInteger` function will come in handy.
 
-## Convert Celsius to Fahrenheit
+## 2. Convert Celsius to Fahrenheit
 
 - Temperature in degrees Fahrenheit is defined as: T(°F) = T(°C) × 1.8 + 32
 - The temperature in Celcius is provided as a `Float` and must return Fahrenheit rounded up to the closest `Integer`.