fix(curriculum): add mid dot to formula (freeCodeCamp#59720)

Author: Supravisor

curriculum/challenges/english/07-scientific-computing-with-python/learn-encapsulation-by-building-a-projectile-trajectory-calculator/660400f02cf3a76795b82d4e.md

@@ -12,7 +12,7 @@ The first thing to set up is a method that calculates the displacement of the pr
 Create a method `__calculate_displacement`, which has only `self` as a parameter, and return the displacement of the projectile.
 
 Use the following formula to compute the projectile displacement:
-\\[ d = \frac{v \cdot \cos\theta \cdot \left(v\cdot\sin\theta + \sqrt{v^2\sin^2\theta + 2 \cdot g \cdot h}\right)}{g} \\]
+\\[ d = \frac{v \cdot \cos\theta \cdot \left(v\cdot\sin\theta + \sqrt{v^2 \cdot \sin^2\theta + 2 \cdot g \cdot h}\right)}{g} \\]
 
 In which $d$ is the displacement, $v$ is the starting speed, $\theta$ is the angle and $h$ is the starting height of the projectile.
 For $g$ you can use the `GRAVITATIONAL_ACCELERATION` variable.