Fix docstring

Author: blegat

src/comparison.jl

@@ -315,14 +315,18 @@ An iterator for generating monomial exponents for monomial
 ordering `M`. The type of the vector of exponents is the type of
 `object` and is length (i.e., the number of variables) is `length(object)`.
 
+Note that `object` does not have to be zero, it just needs to implement
+`copy` and `setindex!` methods (except for `Tuple` which we handle with a
+special case).
+
 See also [`monomials`](@ref).
 
 ### Examples
 
 The following example shows how to generate all exponents of
 monomials of 2 variables up to degree 2.
 ```jldoctest
-julia> collect(ExponentsIterator((0, 0), maxdegree = 2))
+julia> collect(ExponentsIterator{Graded{LexOrder}}((0, 0), maxdegree = 2))
 6-element Vector{Tuple{Int64, Int64}}:
  (0, 0)
  (0, 1)
@@ -334,7 +338,7 @@ julia> collect(ExponentsIterator((0, 0), maxdegree = 2))
 Note that you can easily generate the tuple of exponents
 of arbitrary length using `ntuple` as follows:
 ```jldoctest
-julia> collect(ExponentsIterator(ntuple(zero, 3), mindegree = 2, maxdegree = 2))
+julia> collect(ExponentsIterator{Graded{LexOrder}}(ntuple(zero, 3), mindegree = 2, maxdegree = 2))
 6-element Vector{Tuple{Int64, Int64, Int64}}:
  (0, 0, 2)
  (0, 1, 1)
@@ -343,7 +347,7 @@ julia> collect(ExponentsIterator(ntuple(zero, 3), mindegree = 2, maxdegree = 2))
  (1, 1, 0)
  (2, 0, 0)
 ```
-You can also change the monomial ordering as follows:
+You can also change the monomial ordering and use `Vector` instead of `Tuple` as follows:
 ```jldoctest
 julia> collect(ExponentsIterator{LexOrder}(zeros(Int, 2), mindegree = 2, maxdegree = 3))
 7-element Vector{Vector{Int64}}: