Fix small typo in mechanical-vs-software-solutions.tex (#24)

fundamentals-of-control-theory/application-advice/mechanical-vs-software-solutions.tex

@@ -6,7 +6,7 @@ \section{Mechanical vs software solutions}
 building a robot, but we often allocate just two days for software testing.
 Despite this, teams still field competitive robots, which is a testament to how
 simple and easy to use the FRC software ecosystem is nowadays. Focus on a
-reliabile mechanical design first because a good mechanical design can succeed
+reliable mechanical design first because a good mechanical design can succeed
 with simple software, but the robot can't succeed with unreliable hardware.
 
 The solution to a design problem may be a tradeoff between mechanical and