refactor: use RealI/O instead of RealI/OArray in more than one inputs…

…/outputs

src/Blocks/continuous.jl

@@ -543,8 +543,8 @@ linearized around the operating point `x₀, u₀`, we have `y0, u0 = h(x₀, u
     else
         size(D) == (ny, nu) || error("`D` has to be of dimension ($ny x $nu).")
     end
-    @named input = RealInput(nin = nu)
-    @named output = RealOutput(nout = ny)
+    @named input = RealInputArray(nin = nu)
+    @named output = RealOutputArray(nout = ny)
     @variables x(t)[1:nx]=x [
         description = "State variables of StateSpace system $name"
     ]

src/Blocks/math.jl

@@ -46,8 +46,8 @@ Output the product of a gain matrix with the input signal vector.
         nin = size(K, 2)
     end
     @components begin
-        input = RealInput(; nin = nin)
-        output = RealOutput(; nout = nout)
+        input = RealInputArray(; nin = nin)
+        output = RealOutputArray(; nout = nout)
     end
     @equations begin
         [output.u[i] ~ sum(K[i, j] * input.u[j] for j in 1:nin)
@@ -68,7 +68,7 @@ Input port dimension can be set with `input__nin`
 """
 @mtkmodel Sum begin
     @components begin
-        input = RealInput(; nin)
+        input = RealInputArray(; nin)
         output = RealOutput()
     end
     @equations begin

src/Blocks/utils.jl

@@ -157,8 +157,8 @@ Base class for a multiple input multiple output (MIMO) continuous system block.
 """
 @component function MIMO(; name, nin = 1, nout = 1, u_start = zeros(nin),
         y_start = zeros(nout))
-    @named input = RealInput(nin = nin, guess = u_start)
-    @named output = RealOutput(nout = nout, guess = y_start)
+    @named input = RealInputArray(nin = nin, guess = u_start)
+    @named output = RealOutputArray(nout = nout, guess = y_start)
     @variables(u(t)[1:nin]=u_start, [description = "Input of MIMO system $name"],
         y(t)[1:nout]=y_start, [description = "Output of MIMO system $name"],)
     eqs = [