fix typo in documentation

Author: jbytecode

docs/src/index.md

@@ -3,7 +3,7 @@ A package for Multiple-criteria decision-making techniques in Julia.
 
 ## The problem
 
-Suppose a decision process has n alternatives and m criteria  which are either to be maximized or minimized. Each single criterion has a weight _0 ≤ wᵢ ≤ 1_ where sum of _wᵢ_ is 1. _fᵢ_ is either maximum or minimum. _gⱼ(.)_ is the evolution function and it is choosen as _gⱼ(x) = x_ in many methods. A multiple criteria decision problem can be represented using the decision table 
+Suppose a decision process has n alternatives and m criteria  which are either to be maximized or minimized. Each single criterion has a weight _0 ≤ wᵢ ≤ 1_ where sum of _wᵢ_ is 1. _fᵢ_ is either maximum or minimum. _gⱼ(.)_ is the evolution function and it is chosen as _gⱼ(x) = x_ in many methods. A multiple criteria decision problem can be represented using the decision table 
 
 ![](images/generalformula.png)