fix indentation; add explanation

docs/src/variables.md

@@ -738,8 +738,7 @@ julia> start_value(y)
 
 ## [The `@variables` macro](@id variables)
 
-If you have many [`@variable`](@ref) calls, JuMP provides the macro `@variables`
-that can improve readability:
+If you have many [`@variable`](@ref) calls, JuMP provides the macro [`@variables`](@ref) that can improve readability:
 
 ```jldoctest; setup=:(model=Model())
 julia> @variables(model, begin
@@ -764,6 +763,7 @@ Subject to
 
 ```@docs
 @variable
+@variables
 owner_model
 VariableRef
 all_variables

src/macros.jl

@@ -644,9 +644,9 @@ end
 adds groups of constraints at once, in the same fashion as @constraint. The model must be the first argument, and multiple constraints can be added on multiple lines wrapped in a `begin ... end` block. For example:
 
     @constraints(m, begin
-      x >= 1
-      y - w <= 2
-      sum_to_one[i=1:3], z[i] + y == 1
+        x >= 1
+        y - w <= 2
+        sum_to_one[i=1:3], z[i] + y == 1
     end)
 """ :(@constraints)
 
@@ -656,10 +656,13 @@ adds groups of constraints at once, in the same fashion as @constraint. The mode
 Adds multiple variables to model at once, in the same fashion as `@variable` macro. The model must be the first argument, and multiple variables can be added on multiple lines wrapped in a `begin ... end` block. For example:
 
     @variables(m, begin
-  	x
+      	x
         y[1:2] >= 0
         z, Bin, (start = 0)
     end)
+
+!!! note
+    Keyword arguments must be contained within parentheses (refer the example above). 
 """ :(@variables)
 
 """