docs(references): added documentation for init method for MathOptInterface

Author: gkantsidis

docs/src/reference/reference.md

@@ -386,10 +386,20 @@ api.compute_ising
 api.compute_mixed_ising
 ```
 
+```@docs
+api.QumoResult
+```
+
 ```@docs
 api.compute_qumo_positive
 ```
 
 ```@docs
 api.compute_qumo
 ```
+
+## `MathOptInterface` and `JuMP`
+
+```@docs
+MOI.init
+```

src/init.jl

@@ -24,6 +24,8 @@ module MOI
             __jump_ext = __modules[__index_of_jump_ext]
             Optimizer[] = __jump_ext.Optimizer
         end
+
+        return nothing
     end
 end